Doug's right.
The circuitry that connects the display board and buttons with the rest of the unit is pretty serious stuff, and it's not designed to be detachable.
I don't know if you could hack it and rig some kind of extension cord or not. I'm not sure I'd want to try, considering the unit's cost.
However, the serial interface on the back of the unit allows you (with some fairly inexpensive circuitry) to mount it out of sight and at least
control it remotely, if not
see it. Look on this BBS under the heading "Projects" for descriptions of the interfaces some folks are doing for this.
There is also a product called the MP Shuttle, which is a trunk-mounted hard disk MP3 player with a LCD control/display on an extension cord. It's not as feature-complete as the Empeg, it doesn't have properly-shock-mounted drives, and I've heard one report of difficulty fitting it with large-capacity hard disks, but I think it's more along the lines of what you're talking about.
Tony FabrisEmpeg #144