You know, there are many people who calls VaM to be extremely complicated and overblown, even without a mighty feature like this?
No offense at all! I like your idea very much!
BUT, with only some vew additional steps, it is allready doable now.
Not as simple as you have pictured it, and not that handy, by far!
But you can relatively easy do this by using DAZ3d and a 3d modeling tool like Blender.
I don't know if you allready know all of this, but I want to shortly explain it for maybe other readers:
-Install, open, learn the very basics of DAZ3d.
-Get yourself a copy of the original Genesis 2 figure, that is used by VaM.
-Get rid of the surface smoothing and export the figure as OBJ for a single time... you can re-use it afterwards.
-Open that exported figure in the 3d tool of your choice.
-Edit the mesh without adding or removing any vertices.
-Go to DAZ3d and use the morph-importer to create a full-body morph that works in DAZ3d, and save it.
-If the Genesis 2 morph works in DAZ3d, it works in VaM, too.
It is not that simple as only moving some vertices around in VaM,
but instead of learning a mesh-editor included in VaM, you can use the one of your choice.
You "only" will have those additional steps in DAZ3d.
By the way: The creators of VaM are planning a funktion, included in the future VaM 2.x, to import completely custom shapes/meshes! This will still not be as easy as pictured in your idea, but IMHO it comes very close!