How about a hotel like Disneyland Paris' Hotel Cheyenne with its own park entrance behind Frontierland? The Hotel Cheyenne is a great place to hang out. It's so spread out that a resort like it could offer Disneyland guests a nice respite from the crowded park. International guests on short visits to America might like to experience more of our western culture, even if it were of the artificial Disney variety.
And maybe there could be a Buffalo Bill-type show, campfires, hay rides, and a small, free exhibit from the Gene Autry museum. Perhaps some of the horses could be kept there to improve the atmosphere. Robert A.M. Stern's group could contribute their usual fantastic designs.
There could also be an exit from the new Frontierland area that would be a shortcut to the Mickey and Friends parking lot. This would thin out the sometimes miserable crush of people exiting the park after the fireworks.
I wouldn't have it be an additional park entrance though--except for people staying at the Frontierland Hotel--because the wonderful trip down Main Street should be the way most guests enter. Hotel guests could still have Walt's red carpet entrance experience by passing through a western/Virginia City-like Main Street.
I also wrote a shorter version of this under the comments to Al Lutz's Oct. 19 forum.
Forgive the dupe.