A really incredible cliff setting is Lava Point at the Ritz-Carlton in Kapalua (which is on Maui)! We are having our wedding there, but we've got too many people so our ceremony will be on a lovely grassy knoll just above the Point. Check out their pictures on their website: Maui Wedding Planners: The Ritz-Carlton, Kapalua Weddings. It would work perfectly for your very intimate wedding as well, as they limit the amount of people on the cliff to 8 (I think).
The Ritz is expensive, but in our experience with them thus far, YOU GET WHAT YOU PAY FOR! The service there simply knocked our socks off, and everything about the resort is peaceful, romantic, and simply stunning.
Since cost is a concern, if you didn't want to stay at the hotel (which is having ridiculous deals now that travel is down so much because of the economy), there are much less expensive hotels very close by that you could stay at while still having your ceremony at Lava Point. One in particular that we will probably have our guests at is the Mauian. http://www.mauian.com/accomm.htm
Good luck, and happy searching!