In the automotive world when you have to make changes to anything hardware related, it is extremely difficult. The process would have to change from the CAD drawing, to wiring, to testing, to production line... and many more details. Also, if you ever peel the skin of the Karma off, you will see that it is EXTREMELY packed. There is basically no other place to put the existing CIU.
The water issue is not the CIU location's fault. The CIU Location was supposed to be a dry spot but other parts and design issue caused the water to trickle onto the CIU.
If anyone wants to try to relocate the CIU themselves, it is definitely do-able. Just extend all the wires and make sure you bolt the CIU down horizontally as it is now. It has a accelerometer onboard that would estimate navigation positions in case the GPS satellite reception cuts out. That is currently calibrated to assume CIU is horizontally mounted.