I believe that even a small shark will grow pretty big for most any tank - I think they all get up to at least 3' long. That's wider than large tanks usually are. The ones that sit on the bottom don't care as much about space, since they aren't as active, but you still need a tank big enough for them to turn around at full size and to stretch out fully. Especially one that actually swims around constantly... they need so much room. Take a look in a public aquarium some time, that is the size tank they need (and even some of those look pretty small to spend an entire shark lifetime in...).
If you decide to get one, you need to have a plan for when it outgrows its tank before you get it... I don't think most public aquariums want overgrown sharks, and once it has outgrown your tank the local fish stores aren't going to be able to take it either. You don't want to have a 3' monster and no one who wants it. Maybe an indoor pool for it when it grows?