The adjustable prosthetic hand project

I see a lot of neat designs for prosthetic hands out there, but in order to modify them for different size, one will need to be able to do some pretty fancy CAD work. So I am starting a project (contributors are welcomed!) to make a design that is:
1. easy to print
2. made of elements that can be used to assemble for different sizes by gluing standard spacers.
3. adaptable (eventually) to electronics.
4. modular enough to replace partial fingers, full fingers, or full hand.
I'm using Sketchup for the CAD work, and will be printing out on a Prusa I3.