Here are a few builders:
www.inrangec2.com865-932-6509
www.ohiorapidfire.com937-332-0833
Here are some sources for parts:
www.k-varcorp.com702-364-8880
Sources for Krinkov Grips:
http://www.vemon.com/
www.vemon.com508 326-5691
As with any "contract for labor" or parts...ALWAYS call and speak with the individual providing the desired services. Find out specifics like turnaround time, cost, warranty, etc.
TALK WITH OTHERS ON THIS BOARD AND ASK THEM FOR THEIR INPUTS ON THE GUNSMITH OR PARTS SUPPLIER IN QUESTION.
Make sure your weapon is "spec'd" before it comes back to you. Proper headspace, proper tolerance around the bolt locking lug, etc. etc. The last thing you as a shooter needs to happen is an "out of battery" discharge. This is important!
When you're thoroughly satisified, box it up and send it away!!
KF