They haven't made any mention of making another one as far as I'm aware.
We may not see any new Home Console Pokemon game until the Wii U comes out around November this year (suggested date).
Personally I don't want another PBR. I want a new Stadium with the Minigames and everything. Colosseum wouldn't be bad either, but I prefer having a new Stadium Game. With the Gym Leader Castle, Mini Games, Game Storage, and everything.
*crosses fingers cause of the "reset" clause*