OK guys, just want to give you all an update. Boards will be here next week. Price will be the same as my SB4000 boards (they end up being about the same size), with a discount for multiple boards. I am adding them to my white market thread today, please check there a little later for ordering info and refer all ordering questions there. PCB panel contains 4 channels of Blend, Power Supply PCB, and 8 dual TRS pcb mounting boards (see below).
There were some design changes on the final version I wanted to fill everyone in on.
After building one up, my opinion changed regarding breaking the board into 2 dual channel boards. It was very easy to build and went so smooth that I decided to leave it as a 4 channel board. And since everyone has expressed interest in building 4 channels anyways, it seemed the logical choice.
The ribbon cable/DB25 connector idea is gone. It sounded like a good idea, but it proved to be a nightmare at every step of the way, and if it was a nightmare for me then that means it would be a nightmare for you, so in the end I decided to abandon it. Now, if you want to use a DB25 conector you still can, but you'll need to use a soldercup connector and terminate each wire individually.
Now, for each channel you need 4 connectors (Dry In, Dry Return, Wet In, Blend Out). With four channels that's 16 connectors, so you're not going to practically fit 16 XLR's on a 1U, you could get by with 3 each for each channel and use a Y Cable to split for the Dry In/Dry Out for a total of 12 XLR's (doable in a 1U). If you want all 4 connectors right on the enclosure though then TRS is the logical choice.
I have made adapter boards for the Neutrik slim line PCB TRS connectors (easily available and low cost with multiple versions available).
Example:
http://www.mouser.com/ProductDetail/Neutrik/NRJ6HH/?qs=sGAEpiMZZMv0W4pxf2HiVyYx7%252bjPVsMuVYeO%2fPFCEqk%3d
Each board holds 2 of the TRS connectors on .675" spacing. Daniel's cases will acommodate these TRS boards with the boards turned vertically (so 2 rows of 8 ). You should be able to turn them vertically for modushop cases as well (I haven't verified this yet), for parmetal there is not enough vertical height, so you will need to keep them horizontal (but can easily fit 16 across at the .675" spacing).
I'll post a pic of the layout later today. I can't do any fancy unit pics until the boards come in and I build one up.