I'd be interested in seeing your mock up. I'm probably going to build one of these in a few weeks if my CES plans work out and I end up with an 8 hour drive alone in a car with no empeg. The challenge really is miniaturization, as the box needs to be compact enough to fit comfortable in any car you find yourself in.

A few ideas i've had are: 1) No sled. I've got an extra sled, but I don't see this as getting enough use to worry about plugging a few cables in when I want to use it. 2) Padding - I'm thinking a foam ring similar to the orginal packaging, but a bit thinner. 3) Screen protector - unsolved - if it's not installed, it's not going to have a convienient place to rest, and is gonna get kicked around and fall over. 4) Minijack output would be usefull for those headphone or aux-in times.

anyways, those are just some random ideas I've had while thinking about building one myself. I'm interested to see what you come up with.

Matthew