Under the Seat?
I put mine under the seat... I don't know if everyone has the space I have under there (air box removed for triple K&Ns), but I put a rag, registration, and small tool kit in the space I had.
Even if your air box is still there, you should be able to get those cards in the tool kit that comes with the bike (maybe?).
I realize that under the seat isn't most convenient, but hey, if a cop has you pulled over, this is the least of your worries.