I've just seen the Kickstater video, and I've seen you mention you are sending data to an Arduino. But it looks to me like there is no Arduino in the mix, unless it's the OpenROV BeagleBone Cape you mention in the FAQ.
Have you looked into the RaspberryPI? combined with the GertBoard it can easily replace both the BeagleBone and the Arduino you use as sensor/output connector, and it will lower the cost a lot:
from 90USD + 30USD of the BeagleBone + Arduino it will go down to 35USD + the cost of the board (still unknown yet): 50USD is 10% the cost of the ROV.