Sorry, but you don't know enough to warrant a custom frame if you "don't know what they meant...that tubing and geometry are very important."

Hey, neither do I, but maybe someday I'll think about getting one if I can't find what I'm looking for. I kinda doubt that'll ever happen though, because there are SO MANY bikes out there. If you can't find something you like you aren't trying hard enough. Does it really cost that much to ship a bike to Japan? Or if having a drilled fork is the issue, can't you just buy a roadie fork and install it on whatever bike you buy?