I've got an idea for a portable MAME arcade.
Dig this : A bartop made of 5/8" plywood, it uses a laptop folded backwards, so the screen is viewable and the rest is hidden behind it. Connected to the laptop is the car adaptor, connected to that is a motorcycle battery, connected to that is a battery charger.
When the arcade is not in use plug in the battery charger and it will charge the battery. An auto battery should power a laptop computer for many many hours, I estimate 12-24, but it wouldn't matter as you could plug it in to charge when not in use.
An auto battery gauge could be present on that back.
Yup, I've given allot of thought to this and will eventually build it.
It's "portable" as in it powers itself and can be carried between the vehicle and the destination without much grunting.
Practical? No, there is no good reason to build an arcade machine that can be brought on picnics.
Groovy? Yes, the fact that it's an arcade machine that can be brought on picnics

I will call it MAMEboyAdvance!
Dig it?
Craig