I've got a nice set up I purchased a few years back. Basicly it's a standard cage for braze-on mount, there is an extra piece shaped like a cross, the cross bar being just wider than the handle bars. This additional piece has 2 holes to attach it to the cage pluse 4 hole on the cross bar. 2 very thin U bolts wrap the bar on each side of the stem and connect to the cross bar..easy enough. You can kinda see it here, if you need more, you'll have to wait until Thursday when I get back.

I'm too slow, Bianchigirl has a better pic anyway. Oh, and it doesn't bounce at all