I read earlier about someone complaining the default vibration notification was too long for their taste.(Can't find the original post) Just found that you can create your own customer Vibration patterns. It's under setting-->sound-->device vibration then at the bottom of the pick list you can choose "create" and an interface if provided to create your customer vibration pattern. You can make it pretty much as short or as long as you want.
Just thought i'd share.