I recently helped build a high-end gaming system for a friend -- somewhat of a 'spare no expense' deal. After considering the CM Cosmos II, the Lian Li PC-P80NB and ultimately settling on the Corsair Obsidian 900D, months later he is thinking about swapping to an In Win case we just recently found: the tòu. This is an $800 enclosure inspired by glass architecture and named after the Chinese word for "transparent", precisely the sort of flair my friend was after.
The tòu uses 3mm tempered glass surrounded by a metal skeleton and is finished with a special coating that turns the outside of the chassis into a mirror when your PC is off. However, when illuminated from the inside with your system on, the tòu's mirror coating becomes transparent, showing off your internal hardware and hopefully reassuring your $800 purchase.