Ok, more whack-ass ideas from me stemming from a thread in For Sale:

Check this item on EBay. A super old school pull out radio that had batteries in it so it could keep working after you gank it.

So, what better to do with that spare 2.5" slot on the empeg, but retrofit a laptop battery in there. Maybe it could charge when the empeg was in the car or powered by AC. Then, it would kick in when the unit was unpowered. Hijack could have an entry for @battery (or however it does the differentiation between home and car).

But, I know nothing about current. Can a laptop battery power an empeg? And can a laptop battery accept charge from the car or ac adapter?

And we could make a cool holder for the battery. Like, a bracket with four holes for the hdd mount. Then, it'd need a wiring harness to patch into the empeg wiring system (which i know nothing about because i've never opened my empeg).

But, this thing would solve some people's desire for a portable empeg. Hm... too bad I couldn't hack this thing up and shoot it out to market. It'd be the money making scheme numbah 1!!