I'm planning on building an enclosure to sit underneath my Nord Stage. It is a 73 key stage, so it has organ keys and I would like to turn it into a dual manual console organ, but with the main difference that you can always leave the lower manual at home for smaller gigs. My plan is to buy a Fatar organ style keybed (look here: http://www.doepfer.de/home_e.htm
) and build a flat keyboard that matches the Nord design but where the Nord can sit on top.
You could do the same, but rather than putting a keyboard on top of it, you could make the electro rack sit recessed in the case, so you would basically have rebuild a Nord Electro keyboard.
There should even be plenty of space inside the case to put equipment that you don't need to access often (say an audio interface or DI boxes).