By the time you buy a used blue Contender and reblue it, you might be better off shopping a bit more and getting one that doesn't need reblueing. There are places like SSK Industries that can chrome your gun, put a black finish on it, etc., but it obviously will cost you.
Also, I prefer stainless steel. With a bit of shopping, a stainless steel Contender frame in excellent condition could probably be obtained for $250 or less and a stainless steel barrel (maybe not chambered for the exact cartridge you want though) in the $150 range.