Hey John,
About contracts:
Sorry to say, but many copywriter's that I know don't even use contracts. I think many look at their up-front fee as a contract... Not sure, but I think many copywriters are afraid they are going to scare people off with the "formality" of it.
I sometimes use them and sometimes don't (probably should every time).
If you want to find some really cheap "prewritten" contracts that you can tweak for your own needs, you can try legalzoom.com
If you're "super serious" and a heavy player, get yourself a good attorney.
One of the best investments I ever made was when I paid $100 to a contract attorney "before" signing a $40,000 agreement with a contractor I was doing work for (it saved my ASS-ets... BIG TIME).
Concerning fee structures:
There is a gal who actually has a fee structure she gets from polling her list of copywriters, but who knows whether they are telling her the truth or not.
I just did an interview with Clayton Makepeace last week and this topic is something Clayton touched on... (fee structures).
I was actually surprised to hear what he had to say about it, but he made so much sense (of course he would... he's Clayton Makepeace).
I won't reveal "exactly" what he said (yet) as I promised my site members that they would get the interview before it was sent out to the general public.