I think you can buy reindeer, but I've heard you really have to have a tall and sturdy fence since they can jump really high. Don't know what they require care wise, I imagine they're similar to goats and sheep?
I used to live a few blocks away from a reindeer farm, "Operation Santa Claus." They have a fairly big herd, probably around 20 or so. The fence is fairly beefy, but not all that much bigger or stronger than an average fence. My guess would be around 6 ft high.
So yes, you can buy reindeer, but I have no clue how they are to keep.
Also, I own a pelt from one and the hair is AMAZING! So soft and warm. The hairs are actually hollow which allow them to be extremely efficient insulators.
I discovered the Reindeer Owners and Breeders Association (ROBA). It definitely seems to be growing in popularity due to their gentle temperaments and relative ease of care-taking. There are several farms that offer bottle fed babies...I'm sure they are a pretty penny though!