Inseam only puts an upper bound on the seatpost dimension and really isn't the most important dimension for me. I'm 6' 2" with a "pants size" 32" inseam, hence I have very short legs for someone of my height. Since I haven't won a Lotto I need to get as large a frame "off the rack" as possible without risking some "vital organs" because of my long torso. Maybe someday I'll get a custon frame, but currently there are other priorities in my life that need the $'s more. As of now I have an old (1986) Cannondale 58 cm (c-t-t) and a newish (2002) Lemond Zurich 57 cm (c-t-c) as my road bikes. Both are OK in terms of fit, but I sure would like the top tubes to be just a little bit longer.