For school project types of purposes, you could create a "multi-instance" dimmer, with 4 "instances" (note: requires 2.0 alpha SDK):
Instance #1: Dim level (controlled by standard remote)
Instance #2: Red
Instance #3: Green
Instance #4: Blue
You could also use three Z-Wave chips, and control each one individually. Or use the "bridge firmware" capability--where your device acts as four different devices but is actually just one chip.
I have an RGB LED lamp in my living room and love changing its colors wirelessly. I'd love to see an official profile for RGB lightsin Z-Wave...
Chris