Hi,
There was rather a lot of discussion on the mailing list archive about related topics recently, so searching the archives might prove informative. However, the main things to know are:
(1) PyGame is essentially CPU-bound rasterization. The fastest way to do this is with the Sprite module, or so I'm told.
(2) Using PyOpenGL instead of PyGame (for blitting, anyway), you instead use the GPU, which is deigned for doing just this. You have to know what you're doing, but it will probably be faster.
In your case, most of your objects are off the screen, so you're probably CPU-bound anyway. If you really need more performance, and you really need to process every object every frame, you'll need to switch to a language with less overhead, like C++, or jitted like PyPy.
Ian