My girlfriend wants a new bike. She's a smidge over five foot, and currently rides a 24" wheeled frame. The seat tube measures 14" centre to top, and about 12" centre to centre.
We're looking at getting a 26" wheeled frame, but to be honest, I've no idea what size frame I need to be looking for. 13" seems like the obvious shot as it's the smallest size around, but 14" frames seem to be much cheaper and more plentiful.
The key thing is that it has the same sort of standover height - 25" directly at the seat tube junction, 26" over the centre of the top tube.

