I ran into the same problem once, my solution was to put a squash and stretch modifier on the object. And then used the wiring parameters to have a control object, control the rotation of the squash and stretch gizmo in the modifier stack, i do say it worked out quite well for what it was.
You can download it here
http://theonlyaaron.animateharder.com/rigs.html if you want to take a look at how it was made, or use it or whatever.