Love the design I like everything about it!! I've been doing my own drawings on something very similar it's nice to see I'm not the only one dissatisfied with current case offerings especially for water cooling. Who really wants to hang a rad off the back with the PSU GPU and Case fan blowing hot air right into it or on the top of the case when that's where all the hot air needs to escape. That's why I like my STC CM Stacker with rad installed in bottom of case but pushing hot air into the case is still a compromise. I especially like the separate compartments perfect solution to avoid heat exchange this is what I dream of over and over again. Simply fantastic I want one!! and steel is fine by me.

I'm a free hand drawer and like to dream lately though my ideas have shifted toward the new Sliverstone Raven design with the i/o at the top of the case. Seem to me a this is a fantastic solution and with separate compartments at the bottom for water cooling and front for HDD's, I think you'd have something just different/efficient/effective/and attractive enough as to attract a major manufacturer unless you want to do it on your own. Mountain Mods did it. Bottom line you'd have to produce substantial results that put the other offerings to shame and I believe you'd have a shot doing so by getting the heat out da box like your doing here. The only thing I would change is a separate compartment for HDD's too with side to side air flow similar to your WC solution. This would eliminate all high heat producing components from sharing that heat produced by the mobo.

My basic Idea for the perfect case:
5 compartments
1-top hinged access w/240mm above i/o (completely vented) down scooped at rear for cable mgmt.
2- main mobo/optical with CM style blower
(with the mobo orientated i/o up top the blower to the right would blow right on RAM and PWM area nicely)
( I see enough room to the left for two EK tube style res. fill at top access to PSU/WC compartment Btm)
3- HDD 5 min. w/side to side air flow front case access so side pnl can stay in place for R&R quick connect not necessary but for one of the drives would be nice.
4- PSU/WC entire bottom
5- Control panel on/off/reset usb esata fan temp and lighting control all integrated

Side panel 240mm fan and clear view mobo compartment only

All within a 12 bay case size scale.
2bay I/O and Ctrl Compartments
3bay Optical
4bay HDD
3bay PSU/WC

Oh well a guy can dream hugh?