The Buell Blast has a very low seat if you're looking for something that handles and stops a bit better than the cruiser style 250s. The sportbike style 250s and 500s are going to be taller but might still be doable. Depends on your inseam. If you've got long legs it's not too bad. I'm 6' but only have a 30" inseam so I can't easily flat-foot most of the bikes that fit my torso.
Might also try checking adds for used bikes that have already been modified for a shorter rider. That might help make the decision easier.
Edit: Doh! Forgot the official SBN weclome!
That's better.