If the person was willing to do a little bit of bolting on and mail-ordering I think this is still where I'd be
Colt LE6920 OEM2 - $750
Centurion Arms CMR M-LOK - $195
Magpul MOE SL Carbine Stock - $57
Magpul MOE® SL™ Grip - $19
Magpul MOE® Trigger Guard - $9
goes a hair over the $1k mark at $1030 and can't be just bought over the counter at the local gunshop, but it gives me hope that some enterprising retailer might figure out a way to assemble the complete guns themselves and sell them over the counter.
And confirms, in my mind, that the CCU is a $1k gun.