Well, there's two thing I can think of off the top of my head...
Cyb - Advanced Forum Rules
This one has a full page list of the rules appear, and the user must accept them. I do believe it has the ability to set a different page of rules for different forums/boards.
New Thread Posting Rules
This one has the list of rules appear every time a user creates a new thread. I'm pretty sure that you can set different rules for different boards.
I hope either one is what you're looking for.