Here's an option based out of the South Coast.
http://treasuretoursjamaica.com/index.cfm
Edit: The last I knew (feb '11) Lover's Leap main tourist point it closed. You can still go up there and walk around and get the views, you just can't go to the "official" look out point or the restaurant.
I've never been to Mayfield so I don't know if that would take up a whole day. I would personally suggest YS Falls, Appleton Rum Tour, and Black River boat ride. If time allows you could take to the boat out to Pelican Bar and while driving you can go through Bamboo Alley.
Are you planning on renewing your vows at one of these locations?