If you care about attack penalties, Oversized TWF helps a bit.
Only reason to dual wield whips would probably be some crazy trip and disarm build, and why you don't just rely on AoOs I wouldn't know. In any case, a high strength, large a size as possible, build with Imp. Trip and Disarm, possibly using Setting Sun throws or something. Also possibly using the dragon mag feat to hit with two weapons on each provoked AoO. Still not a great idea...