Years ago (1974-75) I had a 75 pound Leopard tortoise, I imported it from a person that was located in Johannesburg South Africa, Somewhere I have a negative of it with my niece sitting on her, But I can't find it. Someday I will come across it. That is the biggest one I personally have seen but have heard of larger ones. Where this one was from they do get frost at times,but leopards do not hibernate. I have a female that is 4 years old and she is the first one out on chilly mornings, before the sulcatas. I only have the one leopard, but several sulcatas.
Well know looking at 10ftx10ft in m I can just tell you that you can't make the enclousure much smaller as leopards grow a lot, but if you think it's too big well you might be able to make the enclousure a bit smaller with the condition of having and outdoor enclousure (doesn't have to be giant, but quite big) and you can also take your tort out for walks and the put him/her back in the enclousure, as tortoises need to exercise. So in the end what im trying to tell you is that i think you can have smaller enclousures but then take your tort for walks.I do this with my Russian as I don't have much space.
Yeah i wont be buying a leopard any time soon. It would be incredibly cruel as i wouldn't have sufficient space. I will stick with my russians for now!