Tonttu: There is no particular "relationship" between height, inseam, etc. However, standard bike geometries are based on "average build" and it sounds like you have a short torso/long legs. As a very general rule, bike fittings these days start with top tube length and work from there. You would end up with a smaller frame, more seat post extension, and spacers/up-tilted extension to get the bars up somewhat. Your best bet would be to look for frames which have relatively short top tubes (in contrast, Lemonds are known for having relatively long top tubes for a given frame size, while some of the Italian frames are shorter; Merlin used to offer a short top-tube option, although I don't know if they still do). Since women typically have the short torso/long leg build, the women's design Treks, etc. are closer to your proportions (if they come in sizes large enough). Since I'm in your "grouping" (just under 5'8" and 32" inseam) I ended up getting a custom frame. There is a lot of argument about crank length vs. leg length, again as a real general guess, you're in the most-common 172.5mm area.