shape rigging works in various apps. A couple years ago I made a version in Houdini and a Mel script in Maya to ease the repetitive task of setting up the constraints or expressions.
Recently updated a script for XSI, now that shape rigs(their contraints) can be mixed "against" other animation types, making the method more useful than in its early SI3D days.
It can really speed up certain goals and more easily allows things like deformation operators applied to entire rig etc.
I'll add some more external and internal shape rig examples later.