There's also the
powder alliance for those based on the west coast near one of the partner resorts. This one seems a little different since it's a benefit for top-tier passholders at each of the resorts and allows for 3 days at each of the other partner resorts. Currently at Stevens Pass a Premium Pass is $649 for new members. One of my friends did this for a season while on a long road-trip and seemed to like it.