I would suggest russians, just because they are so easy to keep in almost any situation. If you keep them outdoors, make sure you build an impenetrable fortress, because they are great at digging and climbing (a double threat). I built my outdoor enclosure so that there's chicken wire over a foot beneath the soil, and a locking top with heavy hardware mesh. Even then I see them trying to find ways out every now and then. they aren't out there much as it is anyways (I live in upstate new york).
They are good at handling extremes, because in their natural habitat they hibernate when it gets too cold, and estivate (SP) when it gets too hot.
They are certainly a small tortoise, but there is a big variance between males and females. Some males don't get much bigger than 5", and I have a female that is about 10" (and her daughter that I hatched in november is already closing in on the 4" mark!). They have great personality too.
Also, if you go with russians, try to buy CB, and think about the possibility of eventually breeding them (fight the good fight
).
But that's just based off my personal opinions of them. They are my favorite species by far.
Other than that, the other mediterranean torts are great for your situation. Most stay small enough to be easily housed indoors. Some greeks and marginateds have been known to get pretty large (the females of the species), but you can expect them to stay relatively small. Usually under a foot in shell length, closer to 14" for the marginateds.
Happy hunting.