Mine is 27.5". I am sure with the low seat I would be fine. My R6 was 32.3 seat height. I could manage it but it got a little dicey sometimes in the parking lot. I never did drop it but it came close a few times... most notably when I got pulled over by a cop. It was very embarrassing.
I am just concerned about buying a Ducati used. I have heard that service is expensive and that having one without warranty might be expensive if something goes wrong with it. You never can tell if the bike was abused/neglected mechanically from looking at it.
The 2 valve air-cooled motors are very reliable. They do run hotter than a liquid cooled i4 though so you will feel that heat when not moving. Also, Ducati motorcycles don't sound like other bikes. That might be a little unnerving until you get used to the sounds they make... especially if it has an open clutch cover.
If the bike is clean, low mileage, has maintenance records, and isn't leaking fluids that would be enough for me to pull the trigger personally but you can always have a mechanic look it over if you are unsure.
I have been extremely happy with my M1100 EVO. Lots of grunt and great looks. Very fun to ride in the twisties.
