Also questioning the whole "boutique AR" thing. High-end 1911s are another story, lots of hand fitting and highly skilled labor make for an end product that's flat way better than what you can get "off the rack". But the AR platform doesn't really lend itself to, or require, that much gunsmith-type labor. You take high quality parts, which are abundant, and put them together and you end up with a rifle that shoots better than 99% of shooters. The only possible exception I can think of would be long-range highpower competition guns, where the space guns from makers like JP and Tubb really shine.
That being said, I would think about the build-your-own route (I did, got exactly what I wanted and paid less money). Or with a reputable manufacturer such as Rock River, DPMS, Bushmaster, etc. Take the money you saved and spend it on high-end optics alternate upper assemblies, and other accessories such as the TG foregrip you mentioned (an excellent piece of gear BTW, you can fit a whole spare bolt in there!). Money is much better spent in this market, because it's definitely "get-what-you-pay-for" territory. Lotta junk out there. You'll find that things like optics, rail forearms, stocks, and other goodies quickly end up costing more than the rifle did. No $600 gun turns into a $2000 gun faster than an AR, I've got the bank statements to prove it
Anyway, just food for thought, free advice worth every penny. No matter what you end up with, you'll have fun... ARs are a hoot. Go nuts, really pimp it out, and then post pictures of it. Then we'll all chastise you and tell you to spend more money on ammo and training.
DanO