I'd try this site to start, only because it lets you check by availability (as you know, lots of places are going to be booked during that period, and if they're not, they're likely to have 7- to 14-day minimums) so this should save you some time. In general, I've found renting directly through owners to be a little cheaper for the same house. Good luck.

http://www.villascaribe.com/Content/459.htm