Take a look at these frames, you cut the frame rails yourself and its your gun with your custom serial number on it. If you have any questions about it being legal, check section A7 in the ATF FAQ and your local laws. I wont give you a direct link on where to go to purchase these (as the post on them a few months ago was deleted cause it looked like I was selling them, I'm not, someone else is), but a quick search on www.AR15.com will turn up the right place, they sell both Stainless steel and steel frames and slides.
You can use a 3/32" face-width woodruff keyseat cutter (or end mill) to cut the rails (a 3mm cutter would be best, as it cuts the rails only .001" thinner than the spec, but costs a crapload more), then finish them off with the Brownells rail file. I know, I know, lots of people hate the finger thing, I think it looks bad too.
Kharn


You can use a 3/32" face-width woodruff keyseat cutter (or end mill) to cut the rails (a 3mm cutter would be best, as it cuts the rails only .001" thinner than the spec, but costs a crapload more), then finish them off with the Brownells rail file. I know, I know, lots of people hate the finger thing, I think it looks bad too.
Kharn