Well things like the iPod are cretianly a more portable alternative. Although they do not have the same flexability and customizability, they can easily be integrated with the car stereo, and taken with you once you're done driving. - A definate plus!
The Muzic Vault is a device similer to the empeg in that it is a car-only pre-amp out unit with capacity for 2 laptop HDDs. I personally think it's interface is it's major draw-back, but it is certianly cheaper new than the empeg ever was!

Does $200 sound fair? or are you unwilling to part for less than $317?