sub-plot brainstorming for a mage game
In reply to Azraile (msg # 1):
You're in a great situation: your own players are creating the game they want. If they're being kept busy, then I would contend that you don't need any other side plots or, if you do, you could probably get the players to come up with them.
If you're having trouble seeing how to make their subplots work, ask them. Even if you have to let the players in on a bit of what's going on behind the scenes, it's probably worth it, because I find that players are usually willing to forget (or roleplay as if they've forgotten) meta-knowledge, if it means that their cool plot ideas will work. Heck, I've known players to happily walk into the jaws of a GM's plot, even when they knew everything about it, just because the game as a whole was going in a cool direction.
If I'm not understanding or addressing your issue, please let me know. This kind of thing really fascinates me.