We've talked about the comics publisher Bluewater Productions a few times around here. Now Rich Johnston has a new article about them and the contracts they offer freelancers: http://www.bleedingcool.com/2009/09/07/getting-in-deep-with-bluewater-productions/
Apparently, most of their creators don't get an initial page rate, but work for a percentage of the profits. This is fine if a book does well, but it can result in the creators earning nothing if the book sells poorly or is cancelled. Also, it's an unusual arrangement in a work-for-hire setting, where the creator does not own the rights to the work.
There are lots more details in the article.
(I should note that our friend and frequent Comicon poster Pat Broderick has worked for Bluewater and expressed his satisfaction with the deal he got from them. It is not my intention to stir up dirty laundry here, Pat. I genuinely want to see Bluewater succeed. But this is an interesting topic, and I think people will want to know about it.)