I rarely use Mike or Vicky in my work and only on occasion have been stumped about how to create a particular character. But there's a ton of stuff out there, as folks have already mentioned, and add into that places like www.animotions.com, where, with a little ingenuity, you can take those comic book characters apart and get all sorts of cool things. That's where I found an excellent motorcycle jacket for the P4guy (from a model that was originally a P3, BTW). It's also possible to take a character whose costume is heavily prop-based and transfer those props to a P4 -- one of my favourite characters, a policeman, was done this way, and I've been told it's even better than the currently available Michael version.

docandraider.com -- the collected cartoons of Doc and Raider