I know everyone loves Surefire. I do t have one yet though. The primary deal breaker for me is not accepting liIon. Is there such thing as a Vinh modded Surefire 6p or something in that range that I can use 16340 or 18650 in?
Check out the P1R Peacekeeper. Surefire, and it takes 18650 out of the box. First one they have done with lithium ion support from the beginning...vote with your dollars, and maybe they will do more!
Not everyone loves Surefire, though. I bought one, and I ended up giving it away. TERRIBLE green tint, XM-L LED (not a big deal, but this was only a few months ago, and the lack of the most modern LED did bother me, given the price), and not a great interface. Sure, they are tough, and have a good warranty, but if you don't want to use it, it isn't worth the money in any case. Hopefully other people have better experiences...I may get another eventually, but my last one was a letdown.
As to your original question, Vinh generally does not mod Surefire lights (with a few exceptions). Difficult to get open, and expensive to repair or replace if something does go wrong. If you want something specific, you should probably email him, and find out if it is feasible.