Are you going to make a library? I would certainly use is. Right now I'm using SURE3208 dotmatrix panels and also a second ATMEGA just for rendering the displays. The first Arduino does all the other stuff and sends text buffers it to the second one over I2C, just as you are doing.
My CastDuino Shield (the second ATMEGA, use the same way you do, well sort of) has the code for connecting LCD, DOTMATRIX LED, VIDEO-out and needs VGA (microvga shield, doesn't play nice)