5. Satellite phone- looked into it a few years ago and a couple of companies rent them for a small fee. Didn't seem too outrageous if a few went in on it together
6. Find Me Spot- very limited and not that great of a choice IMO
A buddy system has always worked well. Seems like one "get-off" and your antenna is history provided a tree branch hasn't already taken it! However, I'd definately be interested in checking it out if someone could figure out an enduro setup that was shock proof and wasn't priced ridiculously high.