Bobby:
You should easily be able to make a bus work as you described. I expect speed with rs485, if you terminate twisted pair on each end into about 120 ohms, can go at speeds as fast as the UART in your processor can go. Just keep the length the stubs as short as possible. Often the cable is routed right to each board instead of forcing it to straightline down the center of the boat. This limits stub length to the traces on the PC boards.

Michael Karas