c that is where the problem is, the top tube clearance/standover thing is really an issue for MTBs in emergency dismounts, but still the likely hood of having both feet flat footed is 1% of the time. Select a bike on how it feels riding, not how it feels standing there. Even when at stop lights, most people only unclip one side so the top tube height shouldn't be a problem if it was a touch tall.

I'm about the same height as you can can ride both large and XL for the 29er MTB, adjust the .5" of TT difference w/ a shorter or longer stem. For the dirt I prefer a shorter stem and longer effective top tube of the XL. With running a large, I can feel that shorter TT when off the saddle efforts. Road bikes I can ride anything from 55cm top tube to 59, but happy spot is around 58 for longer distance rides. My current roadie is the super 6, in 58 (575mm ett) and running a 110mm stem. Great at all distances for both comfort/power.