Snow-Cat Skiing:
A lot of adventure for a fraction of Heli-Skiing!

Keystone:
http://www.keystoneresort.com/ski-and-snowboard/cat-skiing-and-riding.aspx
Cooper: http://www.skicooper.com/snow-cat-skiing
Note; their may be others...
Cooper: http://www.skicooper.com/snow-cat-skiing
Note; their may be others...