I did a full kernel build, wrote the device driver for the LCD screen, am currently writing the driver for the SIM. I have a debian rootfs running on it - its a nifty little linux gadget. I am currently using a bunch of these as part of a linux kernel hacking tutorial for college kids.
I believe there is a lot of potential for these as alternatives to RPi and its brethren for certain applications. If you try to add all the above peripherals to RPi we quickly cross $500 (of course, you would probably not do so in reality).
If any one is interested in more info, message me.
Shameless Plug: I am also looking for consulting ops on such and similar (I have a LOT of embedded and electronic design experience - from vague user spec to full design).
These little systems are quite capable indeed! I remember compiling the Linux kernel on a 1ghz machine with 32Megs of RAM, back in the day .. and here we are with these little machines in our pockets. Fantastic stuff to be teaching kids to use ..
Lots of things seem up your alley, like the need for a per pixel alpha driver for the Kopin display, etc..