Beijing is not a good choice due to the visa situation for nonrev--lots of $$ and you must have sponsor. I can attest to how cold and nasty it is at the Great Wall Mutianyu late Dec.
Maybe Costa Rica. You have a very tall order for 7 pax. Hire date? All pass riders or some buddies? What about San Diego? You can split family members in groups. May I recommend LuxuryLink.com and their sister site, Familygetaway?
Also, homeaway.com for some villas/large accommodations for groups?
Best of Luck and happy holidays (a bit early)