A vibrating alarm is such a "No Duh" feature that I can't believe no one else has done it in a mass market watch. The Casio GW-400J has all kinds of good stuff including Waveceptor atomic time synchronization, solar cells, tide charts, and moon phase indicators. Generally, this is watch for swimmin' and surfin', but the vibrate function would work great for knowin' when to clock out at the library, I guess.
Priced at about $200 and only available overseas, the GW-400J should be hitting our shores very soon.
Review of the Casio G-Shock GW-400J Vibrating Watch [WatchReport]