If you have your matrix displays wired like this article http://playground.arduino.cc//Main/MAX72XXHardware then the LedControl library (http://playground.arduino.cc//Main/LedControl) will work with up to 8 chips. It does not do scrolling though so you will have to roll your own or use someone else's code. I have done scroll code to scroll right to left that's somewhere on this forum but have not seen multi directional scroll code.
First off I like the display matrix, where did you source a white/blue LED matrix as most seem to be red.What code was you using to do the display as there seems to be a lot of flickering of pixels. Is this by design or due to some underlying problem?