Two head units -- I ain't rich like many of you here. The JVC head unit has CD-player, AM/FM radio, 25W+25W amplifier, and AUX-IN jacks (RCA).
The Empeg plays through the AUX-IN of the JVC deck, good enough for me. In this cold climate (-30C this morning), I don't leave the Empeg in the car at all (always good advice), and the self-contained JVC is always there for radio without having to spin up any hard drives.
My project to use a CF card/adapter for /dev/hda in the Empeg is temporarily on hold, as the hardware is currently being used to prototype an unrelated embedded set-up for a client.
Cheers