I think Trek still makes their OCLV carbon frames in the USA - although their website carefully avoids saying that, so it's probably "many" or "most" of their OCLV frames are USA-made.

Other than that I really don't know anything about it ... I expect there is a real difference in stiffness-to-weight and flex tuning, but how advanced a rider you'd have to be to notice the difference, I have no idea.