smashcoll, I am planning a similar trip and have been doing a lot of research. Right now best deal for staying at Disney is to book on cheaptickets.com and use their usave20 promo for 20% off. Promo ends tomorrow.
Next best option would be to check out lmtclub.com, join for free using the promo code TRAVELTWEET. Comparable prices to Priceline but you get the resort name and can cancel per the rules of the individual hotel. Great prices but they don't list Disney brand resorts.
Barring that you can try going to disboards and booking direct with an owner like somebody mentioned above:
http://www.disboards.com/forumdisplay.php?f=29
But if you want really cheap and still really nice you should be looking at renting from a timeshare owner at a property right beside Disney like Silver Lake. These can be found on ebay for as little as $350 for the entire week and you should be able to get a nice big place with a full kitchen. Downside is you would probably need a rental car. However if you are doing Disney the fastest way to get from your room to a theme park is on average (barring exceptions like the expensive Disney resorts on the monorail) to stay at a place like Silver Lake and drive yourself rather than stay at a Disney resort and wait for a Disney bus. What can I say, I'm sick, I actually timed it from the different places we have stayed at.
Early December is absolutely the best time of year to go. Not crowded, good weather and lot of deals to be found.