Thanks for the recommendation! The resort looks great and the price would be OK, but alas, there's small print lurking at the bottom of the page:
* Required a minimum of 4 nights stay for all season
* Required a minimum of 7 nights stay during 20.12.05-10.01.06
So no can do, at least this time around.

Other ideas? And yes, Koh Lanta or Khao Lak would be fine.