In the US you can find a number of atypical meats if you look hard enough. Alligator is raised commercially for this purpose as are buffalo and ostrich. If by exotic, you are looking for something that needs to be harvested from the wild, then you will not find it for commercial sale in most instances. I doubt any place is selling real tiger meat as tigers are endangered in the wild and anybody who wanted to raise them for meat would be overrun by PETA and the like. If you want to eat unusual things while traveling, you will find local "delicacies" where these animals are locally plentiful. If you watch Andrew Zimmer's "Bizarre Foods" on the Travel Channel, you will get some ideas, As an example, I ate at a place called the Boma in Zimbabwe that served eland, warthog, impala, crocodile, elephant, and mopane worms. I think you can find some atypical meats that are canned at Cabelas as well.
Cheers,
Greg