I wouldn't want an amplifier in my dash next to the player. Would give off too much heat and heat up the empeg-- not good for the disk drives.

I have seen amps that were small enough to fit in a space like that, but they were cheap and too low power to give a clean signal even at low volumes. High quality amps require a certain amount of physical mass, as well as decent heat sinks and ventilation. The dashboard isn't the right place for them.

If installation cost is your only problem, I suggest DIY: Get your amp from Crutchfield with a proper installation wiring kit and read the booklets they send along with their stuff. It's a lot of work, but if you're decent with tools you should be able to handle it.