Just a thought off the top of my head. You might be able to convert the Empeg Carry Case pretty quickly for this.

One thing you hve to keep in mind here... the empeg is designed to play in a horizontal position (give or take 8 degrees, more or less) and if you have it stuffed into a backpack, the hard drive is not going to be in proper orientation. This is bad for the disk drive spindle bearings, and will cause premature failure.

When I built my bikempeg, I was careful about the orientation of the empeg, as well as being careful about shock mounting it in an inch and a half of foam rubber on a platform that in turn is mounted on a flexible handlebar.

As far as headphones go... you have to use low impedence, high quality walkman style headphones. The line-outs won't drive larger headphones.

As far as weight... the battery I use weighs about as much as one and a half empegs. Be sure you want to carry that much weight around!

One of the portable MP3 players might be more appropriate in this application.

tanstaafl.