Finally feels like my circuit designs are completed to the point that PCBs for modules is the next step towards building modules. The trimless VCA is virtually ready as-is. The Antilog Generator worked so well that I'm confident joining it with a precise V/F and waveshapers that I've already designed will result in an awesome VCO. These two module types are a good place to get started constructing the Model III EMS!
Due to a lot of investment, and thinking about the module layouts, I'm going to stick with my 3U PAiA FracRak mechanical packaging system, and 3.5mm jacks.