What exactly do you want? A rewriter or just something that will put your words into {|} syntax?
I was working on a rewriter a while back, it has a working thesaurus and it will let you choose synonyms from a list or type them in and it will put it into the article in {|}, but I didn't finish it, so it doesn't actually do the spinning, just the syntax.
Oh, and MAR is pretty good. If you get the tokens 2.0 it can auto-add {|} with tons of words that usually make good sense. You'd have to go through it to make sure things look ok, but overall it's pretty good. Of course you can add them yourself or use the thesaurus as well.
