I just posted a tutorial on the modo forums that might be of interest to you. It involves animating a wire like a mouse or something where one side is moving and the other side is stationary.
There are a couple of techniques that I have recently learned that are new to us CAD peeps but can be very powerful. So if you are interested, check 'em out and feel free to leave your comments.
If you are interested and you have modo - I can shoot you the files as well...