Russians will stay small, ecspecially the males (that's all I seem to see) The only drawback is they are all pretty much wild caught. (but I can tell you when Petco has em' on sale, we usually get a flood of them 6 months later)
Redfoots and yellowfoots are great too. They get a bit larger then the Russians, but not an unmanagable size by any means.
Let us not forget the lovable Hermann's Tortoise (Testudo Hermanni) Males get about 5 inches, females average 10 inches. They are managable but a bit on the drab side, if your looking for color, check into the red and yellow foots.
Just remember when you get a tort, your in for a nice long haul.
Let us know what you decide!
Rusty