I have a ton of experiance with all kinds of marine life, except sharks. I maintain aquariums for very wealthy people. I make about $5k a month from just maintaining tanks. To be honest, I should be paying them. They give me the money and I buy all of the equipment and livestock, and I only get the best of the best. They basicially pay me for me to keep a fishtank at their house. They dont want any part of it, except to be able to watch the fish.
I dont have much experiance with sharks besides the bamboo and nurse shark that we have at the lfs I manage.. Its a suken rubbermaid pond, with glass blocks all around it so the water level is actually about 4' higher than the pond itself. Sharks are hard to find here, hence why I dont have much experiance with them..
As far as coldwater, there really is no budget. Why couldn't I get a chiller?
I can easily catch dogfish near my shore house. Seeing as most of them don't get larger than 4', would it be better to setup a coldwater tank for a dogfish?