back to your initial question. Are you still open for features to include?
Well, I am working with trucks, and trucks don't have a 12V but a 24V electric system.
So it would be nice if if your dc/dc-converter could work with 24V input (which mean at least 32V input voltage).
The physical dimensions of the booster pack should not exceed the dimensions of the stellaris board.
It should be possible to put another booster pack on top of your booster pack, so there should be female connectors for all pins of the stellaris board on top of your board. Concerning the CAN-Bus there should be a 120 Ohm resistor on the board to connect CAN-H and CAN-L and it should be possible to connect/disconnect this resistor between CAN-H and CAN-L by a special solder point for this purpose so that it easy to choose if you want this 120 Ohm connection or not. The can connector should have a 90 degree angle, so that it is possible to put another booster pack on top of your booster pack.
When will your CAN booster pack be ready for purchase?