I'm writing a simulator in Python, and am curious about options and opinions regarding basic 2D animations. By animation, I'm referring to rendering on the fly, not displaying prerendered images.
I'm currently using matplotlib (Wxagg backend), and it's possible that I'll be able to continue using it, but I suspect it won't be able to sufficiently scale in terms of performance or capabilities.
Requirements are:

Cross-platform (Linux, MacOS X,
Windows)
Low complexity overhead
Plays well with wxpython (at least won't step on each other's toes unduly)
Interactivity. Detect when objects are clicked on, moused over, etc. 

Note that high performance isn't on the list, but the ability to handle ~100 bitmap objects on the screen would be good.
Your thoughts?
You can try pygame, its very easy to handle and similar to SDL under c++
2D animation in Python