Thanks for all your Chow help. After looking at all the suggestions and weighing the cost, driving distance, atmosphere, menus, etc., I think we are down to Mr. Stox and the Summit House. A place that will accommodate dinner for 30 people with a wide range of different tastes and sensibilities is hard to plan long distance. Chowhounds rarely steer in the wrong direction.
Both places seem to have decent and similar menus and the costs are comparable and the driving distances are decent. However, the atmosphere in the private dining areas are completely different - outdoor patio with fireworks from Disneyland for one (celebratory atmosphere), wine cellar for the other (classy). Just a matter of preference, either would be nice.
So it comes down to quality of service and deliciousness of food. I would eat at both places first if I could. Any help would be appreciated.