My touchscreen technology is not really secret.  I was planning on using a resistive screen from either trolltouch or KEYTEC.  My thought is that they are essentially waterproof to a few feet, as they are sealed to the surface of the glass.

I have included a picture to illustrate what I am currently thinking.  The central box (without the curved edges) is 17" wide (I increased the space to allow for holding it without touching the screen) 12" high, and 2" thick.  I have removed the back and top so as to allow internal viewing.  I have not included any of the electronics from the MBP yet, as I need to model them still. 

In looking at the internals, I am wondering where and if I could have some longer wires made.  Specifically, the flex cable that attaches the IO board, as I would really like to place all of the ports on one side.  The non-orange wires will be relatively easy to replace.  I am also concerned that they may need to be a certain length because of timing issues.