I do know that some folk have house rule things based on Tome of Battle rules, and those are even posted on forums, and that somehow doesn't upset WotC. I'm not a legal expert, but it would probably have to be something specifically not presented as a way to make money, not sold, and probably presented under fair use somehow.
I think it's ok to post stuff in forums, but (my point was) I couldn't publish it as part of the Codex. But (my other point was) if you find a way to do it I'll support it 100%.