wtex--the first thing to consider when going custom is whether you need to at all. The consensus seems to be that 90% of us can fit just fine on a stock frame, and the "custom" geometry that we'd end up with looks an awful lot like an off-the-shelf frame.

If you want to spend the $$$$, that's fine, but you might not need to. Just something to think about--try competitive cyclist's fit calculator, etc. and see where you end up. You might just be able to buy a stock Litespeed/Merlin/etc. and save a few bucks.