OK, cool. I had seen some Arduino library code for the MCP23008 IO expander, but the shift register solution seemed simpler. Can you daisy-chain these IO expanders the way you can with the shift register boards?

EDIT: Looks like the I2C version can handle multiple chips on the same bus, but the SPI version can't.

EDIT 2: I didn't see your second reply when I posted mine... I'll look into those strategies as well.