Not an option for this project -- it uses a proprietary rule system, so going with a publisher that has the rights to that system is pretty much the only option. (Nor do I want to go to the trouble of rewriting the whole thing to use a generic d20 or 3d6 system instead.) I also have options other than the Big Slimy River, and given the way they rip off everyone they interact with, I'd have a hard time justifying giving them business.