Would also be nice if you can get a custom lower. I have my lowers made by tacticalmachining, and since I'm a 07 FFL holder I can have it manufactured with my name and logos and my own designs. I also find my customers like it when there's a full auto icon engraved seems to up the price a bit.
I already built my lower. It is a black rain reciever with CMMG parts kit. I polished up the contact points and got rid of a little bit of the creep then installed a JP lower powered spring. I just got my trigger scale in the mail so I will have to see how I did with it. The rest of the lower is VLTOR colapsable stock, noveske end plate and JP tuned action spring.
I did cancel my order on the JP modular rail because there was no delivery in sight. I picked up a Troy free float 11" with only the top rail. It seem comfortable and came with the screw on rails like the JP. I am not sure how the weight of these parts compare to others but I am hoping to be right around 8 pounds or less with optics when done.