Check out Davis and Wisconsin, which apparently have the top two exotic/zoo caseloads in terms of numbers (according to one of the zoo/exotic vets at Wisc). Both have zoo/exotics residency programs, which obviously you can only have if you've got a pretty high caseload. Davis is more split up, with a dedicated pet exotics facility, a couple different wildlife outreach programs, and a zoo program. They have a pile of different zoo, exotic, and wildlife-related elective courses during the preclinical years, which I think is really cool. Wisconsin is kind of combined all together - though they don't really do domestic wildlife because there's a really great wildlife rehab organization in town (you can rotate there though). I think there really aren't many pre-clinical electives at Wisc, but interested students meet with the two zoo/exotic faculty as an informal group every month or so. Both Davis and Wisconsin have a primate center on campus, though only Davis has formal elective rotation there (at Wisc you'd basically have to set it up like an externship). The zoo/exotic faculty I've spoken to at both schools are very friendly and enthusiastic. Davis has a student zoo/wildlife/aquatics club that does a lot of neat wet labs, I forget whether Wisconsin has one.
Minnesota has a really fantastic raptor rehab center (an injured California condor got airlifted there rather than Davis, even though it was obviously much further away, because of their expertise). But I didn't get the impression they had a ton of other wildlife stuff, and you sound like you want some variety.
EDIT: Since you mentioned the Serengeti... One of Wisconsin's zoo/exotics faculty is also heavily involved in some international outreach programs. I don't remember if they've got one in Africa yet, but they go to Thailand, Mexico, somewhere else in South America... Like five different sites all together. You can get funding to pay for your trip. They do livestock stuff with the local residents as well as study whatever the local wildlife happens to be.