Just as a further thought:
Allegro Microsystems makes a device called the UCN8532 which can be found here:

http://www.allegromicro.com/sf/5832/

This guy is a 32-bit serial in shift register driving 32 open collector transistors that can sink 100mA each with 40V standoff. Works pretty well at up to 5MHz input. Two of them should drive your two-color array nicely.