You may want to take note of TechReport's X79 motherboard roundup. It has the clearance measurements for most of the vendors' (the usual suspects anyway) boards. The arrangements for models within a vendors range don't differ too significantly in most cases as they tend to utilize the same base PCB layout.
This is the Asus P9X79 Pro for example:


You would need to source an LGA2011 retention kit from Thermalright for the SA. Low profile memory modules would be a must also. Noctua's NH-D14 SE2011 (similar to the SA) has increased memory height clearance cutouts and an LGA2011 retention kit - Tom Logan at OC3D got a 3960X to 5GHz using the same cooler in his R4E review.

If you're considering watercooling then I'm not sure that the H100 represents good value for money/performance. You would likely want to replace the fans, so that 's likely to put you over a hundred quid. If you can handle the idea of assembling the kit yourself (not difficult) then I'd suggest the XSPC Rasa 750 kit which isn't appreciably more than the H100 but offers better performance (RS240) or much better performance (RX240 - same kit, thicker radiator, more cooling surface area)...these have the added advantage of being upgradeable -either with other water cooling vendors components, or XSPC's own new range.

Having a component based watercool setup also means you'll likely have a bottle of coolant/distilled and de-ionized water handy should things get out of hand Towering Inferno style

I was very eager to see how well in practice the i7 3960X would do from the impressive leaked stats that has been teasing us for the past year, how disappointing it all turned out to be. The upside is that my i7 2600K purchase in January '11 was justified by these impressive figures here and much better stability for overclocking on most boards towards 5GHz on water.

I would have bought a 3960X setup but I from reading all the reviews online and watching plenty of professionals testing the chip I can't justify now so will be putting my cash towards a couple GPUs. I do hope that further BIOS updates with the 2011 chipsets sorts out the issues with overclocking and keeping the system stable.

I read elsewhere that 60K PPD from F@H is achievable from the 3960X at stock, this compares to 2700K stock of 31K PPD. Though your better off power consumption wise with the upcoming Xeon E5 1650 for a modest price of £340 per unit.

However, this isn't for gamers at all and should be bought by professionals as was proved by the use of the extra memory bandwidth and use of 12 threads vs 8 for 2700K. All those threads are great but useless until applications are programmed to make use of all these threads, gaming stands no chance because it usually requires no more than 4 threads. The defunct i7 920 has been know for a while now to slightly bottleneck GPUs, the i7 2600K can be had for £230 retail which should look a bargain versus even the i7 3930K at approx. £450.

Actually the estimates were pretty spot on...unless you're talking about some uninformed fanboy/gossip sites,...but then, they always tend to err on the side of sensationalism...of course, if you can supply some links...or even one, that originates from Intel, feel free to share. I follow this stuff very closely, and with the exception of the VT-d and decreased SATA/SAS complement with Patsburg-A (both of which have been known for some time) virtually everything is as shown in the slide decks.

The issue isn't with the chipset ( BIOS update might help individual boards), it's with the initial CPU revision. These chips will take a horrendous (for Intel) amount of vCore. They just aren't capable of going higher. The C2 revision will refine the CPU to a degree -just as the D0 revision greatly increased Bloomfields OC potential from the initial C0 stepping- but SB-E was designed from the outset as an eight core CPU and Core i7 are nothing more than salvage parts running at the limit of LGA2011's 130w specification. In effect the difference between SB and SB-E is that you're sacrificing clockspeed and OC headroom for L3 cache and die area...and games don't generally need a ton of L3.

You're attempting to make an argument based on pricing where the majority of the people buying the platform don't give a rat's a5s:
e-peen. Fastest is better than 2nd fastest....if that wasn't the motivation for some then a dual-Xeon SR-3 wouldn't be hitting shelves after the holiday season. Just for comparison, the SR-2 (dual Xeon Westmere-EX) was quite a popular seller, and...
Workstation performance (rendering, compositing, productivity et al) in addition -or instead of - the gaming aspect. Pricing becomes much more palatable if it comes with a tax rebate. The only reason that WS isn't being pushed at the moment is because VT-d and SAS are non-functional on the initial revision boards/CPU's.

Estimates.... dividebyzero I didn't keep the links for the previews of the well respected sites because my bookmarks are in need of housekeeping and already difficult to navigate - I never read forums for new tech either as I require quality articles such as this - my expectations of Ivy Bridge was taken from the leaked CPU specifications and how they said it could line up against existing Sandy Bridge processors back in approx. May '11. Of course, theory and practice are two different things when you don't actually have something to test that early. I won't proclaim to know every detail from Intel's lineup and some information I remembered has been replaced with more pressing concerns of late.

Chipset.... There are recommended limitations to the amount of vcore to use and going above 1.4v would degrade the lifespan of the CPU - using 1.5v for even 4.9GHz as noted in your link under LN2 is crazy but only used for benching. Stable overclocking for 24/7 use looks like being 4.6GHz (more reports of this issue all over the web). I wonder how the temps would fair Vs SB under water, my 2600K at 4.7GHz, 1.33vcore is 55c on water under load for a 16hour F@H SMP run at room temps of 23c. Running 3960x at higher vcore plus additional cores 'could' push it towards 65c which is a bit too high for my liking. If you were to overclock, I doubt you would go beyond 4.4GHz if your running it as a workstation for stability (to guarantee stability you obviously wouldn't overclock). Seems you need to read every review to see how each motherboard fairs with overclocking (mixed success apparently from when I was speed reading yesterday).

Most of what is known actually begins and ends with a couple of slides. After that it is all conjecture.
None of which has any bearing on SB-E directly...
Bear in mind that your SB platform has the upgrade path of:
2600K > possibly a faster 2700+K > Ivy Bridge (4C/8T)
The upgrade path for SB-E
3960X/3930K > C2 stepping + speed bin increases > Ivy Bridge-E (up to 10C/20T)

Again,
The extreme crowd won't be setting any OC records with SB-E...I thought I'd already made that clear. Likewise do you think your 2600K platform can:
Run quad-SLI ?
Run triple GPU and still have full I/O functionality?
Equal or better a SB-E in Vantage, 3DMark11, WPrime32 or any other accepted performance benchmark ?

Firstly, OC depends on the platform and the particular CPU. I've already provided a link to show that SB-E isn't the world's best overclocker, so what's the point?
The world's best overclocker is an AMD part. Care to state how many HWBot benchmarks a FX-8150 would win over the 3960X ? or for that matter, substitute a 2700K for the 8150.
If absolute clockspeed is the defining pinnacle of performance then every enthusiast should be going for Bulldozer since SB is capped at a 57 multiplier.

Allow me:
Intel DX79SI low: 4.3 (Hardware Secrets) - High - 4.9 (Hardware Canucks)
Also: 4.4 (HT4U), 4.5 (Overclockers.com, Xbit), 4.6 (Technic3D, Legit Reviews, Hardcore Hardware, Hardware France, Tom's Hardware), 4.7 (PC Perspective, Madshrimps), ), 4.73 (OCC), 4.75 (Hot Hardware), 4.8 (HiTech Legion, ComputerBase, Tech Report)
Asus Rampage IV Extreme : low 4.6 (eTeknik), High: 5 (Tweaktown, OC3D, OCLab.pl) Also: 4.7 (VR-Zone), 4.8 (Kitguru, HardOCP)
Gigabyte Assassin2 : low: 4.4 (TechSpot) High: 4.6 (Tweaktown)
Gigabyte X79-UD7 : 4.77 (Sin's Hardware)
Gigabyte X79-UD5 : 4.8 (Tech Report)
Asus P9X79 Pro: 4.5 (Xbit)
Asus Sabertooth X79: low 4.7 (bit-tech), high: 4.9 (Madshrimps)
MSI X79-GD65: low: 4.7 (Tech Report), high: 5 (Guru3D)