I watched a guy do something like that off of Shuksan Arm just outside of the Mt. Baker Ski Area: last season if I remember correctly. He skied off a big cliff, did a back flip, pulled the rip cord, and sailed around on the updrafts for awhile before landing. This was all easily and dramatically visible from Chair 8.
It was off one of the bigger cliffs in this photo which was taken from the chair: