Check out www.saltwaterfish.com
In the the discussion boards under aggressive there are some guys with some pretty sweet tanks with some sharks. there is a guy who built a tank in his basement it is huga and pushing 1000gl's. If you do it right you can keep pretty much anything as long as you have the right living arrangments....I wounder how big a tank I would need to keep a dolphine?
I guess that goes on the fantasy list.
Unfortunaly most dont have the correct living arrangments, one of the guys in the area around my just took all his fish out of his 100gl reef, and is replacing them with a horn shark
, not only is his tank 3x too small but it has over 100lbs of live rock and will give the shark a minimal amount of swimming area. I talked for over an hour to try snap him out of it but he just told me his tank his money. Makes me said knowing that the shark will never be healthy and he will probably go through several sharks before he realizes that it isnt the shark but the owners fault