excellent information faz
I, too, am well versed in the world of turtles and tortoises and couldn't agree more with Faz's opinion that tortoises should be kept outside
they have large lighting demands and need tons of space - I read (at the zoo) that they actually roam for miles everyday (you would want to let it roam free throughout your house like a dog)
only problem is that they dont potty train and the lighting demands (need that UV for digestion)
to be honest with you, I think that you'd be better off and your kids would be far more entertained with a turtle and a pond/turtle tank
if you're a DIY'er you can get a "pond kit" cheap or stock tanks and build it into a nice cabinet
here are my red-eared slider tanks that I have setup now
please note that this lighting setup in no way meets their demands and has since been upgraded
since we used nice material (oak, etc) this cost about $200, but it could easily be done for half price if you used normal wood and just painted it
those are dual 40g stock tanks, which would be plenty of room for most turtles (bold the most)