Check out WRAP (Whippet Rescue and Placement) -- there are whippets available from puppies on up to seniors. The puppies are in Louisiana and North Carolina -- the ones in Lousiana are definitely mixes and the ones in North Carolina may or may not be purebred, but they sure look like whippets. WRAP does not ship, so you have to find one within driving distance.
Senior whippets are a great opportunity to find out whether a sighthound is really your breed. You'll get a dog who's most likely housebroken, not too rambunctious, and it's not a 15-year commitment. Yes, you'll only have a few years with him, but think of the kindness you'll be doing for an old fellow who, through no fault of his own, has lost his home. We've always said that if people knew about the joys of old dogs, no one would be able to give away puppies! And every whippet deserves a sofa to call his own,
There's a fee for the dogs (otherwise, how could they afford to take in the next whippet in need?) but it's very reasonable and varies with the age and condition of the dog. Go to http://www.whippet-rescue.com/available.html for more information.