The target audience is the enthusiast watercooling market.
That's great and all, but it's a small market.
My suggestions were only to help in regards to getting companies interested, which will be much easier if they can market it for more than one purpose. For instance the V2000 has been a popular case for water cooling, it has slots for 12 hard drives and the bays allow for more. It's quite a popular file server case and doesn't require much modification to make it into a great dual loop water cooling case (side vents, which your case already provides).
More than 4 Hard Drives and you really are getting into territory that isn't for a performance machine.
Quite the opposite. The amount of machines I've built through work, seen on forums and such where people have had 4 drives in raid0 for the OS just for the performance and value for money is pretty large (especially non raptor drives). Then there are people who would look at your 2 500GB raid0 storage volume and cringe at how there is not some form of redundancy there.
(and prolly save you some cash on your power bills).
Separating it all into two devices wouldn't save me anything, the HDD's themselves don't use much power at all.