I got a call from Stuart last weekend and the price seemed reasonable. I figured if there was enough interest, a group buy could bring the price down.
In this type of installation, I've typically created a box to mount in the trunk. The ribbon cable lies flat under carpeting nicely. Making the front display look nice isn't too hard if you're handy. You can make a housing out of thin ply and put vinyl around it for a finished look. If you have a spare heater vent, you can create a mount that fits into the hole and blends into the dash. This allows for easy access to the front controls and makes for a great finished look.
There are some undocumented features of the extender board that I might be able to dig up. The design allowed for remote power at the display with a jumper for remote\local power. There was never a need for local power and I seem to remember the display running at a very high voltage. 60v seems to come to mind, but my memory isn't what it used to be.
Take care connecting the small ribbon cable to the empeg motherboard. If you connect the ribbon cable to the header with a pair of pins on the outside of the connector, you'll blow one of the surface mount display fuses. You'll get the flashing blue status light and no visuals. Other than that, do take static electricity into consideration when handling these boards.