dealextreme used to have something like this:
http://www.sourcingmap.com/bike-bicy...r-p-26312.html but free shipping. can't find it on the site anymore. but this mount works well, is simple, and pretty cheap. i've ridden on some bumpy streets and this one works as well as any other mount i've tried (no mount will be absolutely secure for bumpy roads or offroading, imo).