* The first thing I posted (and then removed) is the wrong size.  One would need a 12.1" screen at an 800x600 ratio.  These seem to be pretty expensive with associated controller boards (to HDMI).  I'll work on it.

This probably solves the video issue, and audio since the board apparently only does audio output through HDMI.  One might either replace the speakers in the speaker panel or thread the cable up with the video cable to the screen and replace the screen speakers - or do both.

I'm also thinking it would make sense to have two USB hubs - one totally internal with a wifi and maybe bluetooth or bluetooth keyboard/mouse dongle, and the other as external ports.

The issue then is really the battery as a secondary concern, and the trackpad/keyboard as a primary concern.  They were intended to be USB, but bluetooth should work fine.  It might be a bit tight to find a keyboard the fits exactly, but I was unable to find any laptop-style trackpads that function as bluetooth or wifi - or even that are USB.  It's a pretty specific request; might have to be customized if that's possible.

* It's 800x600 12.1" and I measure 7 1/4" x 9 5/8".