There basically are none. There are a couple out from big-name manufacturers. (It seems like it's Pioneer and someone else.) But they seem to require you to rip all your CDs in your car. There's the PhatBox, but it replaces a CD changer, IIRC, and doesn't begin to have the interface of the empeg.

You'd probably be better off sending to someone to fix. It'd be cheaper and you'd get a better solution. That's not to say the empeg is perfect -- it's not -- but it's still the best that exists right now.