Think I finally decided on a the MIDI 2 CV. Hexinverter.net has a DIY MIDI2CV that pretty much fits the bill. The only issue is it cannot chose how many voices for poly. It's either 1 or 4. But, there is a version of software over on muff's that allows to select how many voices, among other things. At first I was just going to hardwire it under the panel, but I decided that I would wire switched jacks and normal everything for 2-voice poly, but when a cable is inserted, it will break the connection. Should be pretty cool. While I'd like to have a custom one built, I don't know how to write code and it would probably be a lot more expensive to pay someone to build it for me.
The Globals panel is pretty much laid out. I just ordered that last remaining parts needed. Now the big challenge is getting the case designed and built.