Hopefully this is in the right section.
I contacted an ASC user, djbordie, (you'll find his email on his profile) about engraving the lower on my KJ GBBR.
Bottom line: Communications were fast, turn-around time was even faster, and within a business weeks time, I had my lower receiver back and assembled. The price was about a third of what I expected to spend (even including shipping), so I am a very satisfied customer.
He said he can do custom work no problem, but after debating, I went with standard COLT trades. I'll let the pictures speak for themselves. Excuse the cheap point-and-shoot camera.
Highly recommended. I will be sending some more things in the future.
http://www.airsoftcanada.com/showthread.php?t=114860 (some other reviews)