Coyotebuster,
I had thought about using a weaselball for decoying coyotes and bobcats. I was looking at some sites on the internet and I came across one called decoyheart.com. Upon looking at this site they have the predator supreme which is basically a weasel ball mounted on a spring and a about a 3/8" dowel rod. Your idea should work, but you're going to have to drill a hole through the bottom of the weasel ball and attach the spring with a screw thru the bottom, and attach to the dowel rod. I have been thinking about making one myself, and one for my friend. You'll have to get some kind of synthetic fur, or get a rabbit and skin and use some salt or something to tan the hide, then you can use this to cover the ball, thus just living the stick exposed. Drop me a line if you have any questions.
gonzaga