I started to wonder if it is possible to create just one impression in blender and import it to VNE. So that custom offsets would only affect small part of the base mesh and leave the rest of the character intact. This way some custom offsets could be used in many different characters. I am speaking about specialised heads, arms, legs or privates. I think this could really open up possibilities.
One other thing, are the penises going to be changed similar to the nipple system? Although a lot of work to implement, but the possibility for custom creations is intriguing.