I sort of agree with draihl's criticism; when I think of "boutique builders" I think of builders like Maingear, Origin PC, Falcon Northwest, and Puget Systems, maybe Eurocom as well. CyberPowerPC, iBuyPower, XoticPC, and maybe AVADirect are kind of in between the mass-market Dells and HPs, and the boutiques - they offer tons of customizeability, but focus on the gaming crowd rather than the crowd seeking top-end build quality. Not sure if there's a term for it though.
Of course the ones featured in this article are generally more affordable than what I think of as "boutique builders". Maybe the closest analogy is the the old independent shops that mostly went out of business in the '90s. They'd built whatever you wanted, and charged more than Dell, but the build quality could vary, unlike the true boutiques who always had high build quality.
I'll probably follow Dimitriid's recommendation myself and keep my current rig.