Hey John, how did you make out?
If you are interested in having it all taken care of for you in the best way, have you tried Barb's Belize, MagnumBelize and oh, gosh, help me out here gang, I can't remember the other one.
On the other hand, you could do it all yourself. Contact the places you'd like to stay and strike a deal that will not include the cost of commission that would have been paid to an agent. Further, if you search lodgings on this website, you'll find that many resorts already have dive and stay packages.
Then all you have to do is book your airfare.
Or you can find the place you want to stay on your own and once upon your arrival, do a walk-about to some of the dives operators that interest you. Have talks with them, and when satisfied, negotiate for a block of dives. Most, if not all of the shops, have a better deal on your dives if they know you will be diving with them consistently or for a certain number of dives.