mod it- snobunje makes a little rubber strap that hooks to the eye hook. it will not let the snobunje come off of the ski. they are like 5 buks and will save you from "spending alot of time looking for a $100 bunje." your method works very well, but when used in conjuction with a snobunje is the ultimate. or the double whammy, when pointed up hill, move the back end of the sled out of the trench, pack down a trail in front of the machine (think of a ramp) and put a snobunje on each ski (providing you have at least 2 friends and 2 bungees). most of the time the sled will accellerate up the hill and continue on.
for solo stuck situations, go slow, take your helmet off and start digging. move the snow from one side of the skid/tunnel, stomp the snow next to the skid down to pack a nice platform. lift the rear of the sled up and over onto the packed snow. stomp as much snow down in front of the machine as possible (in between the skis, towards the track). pack a trail atleast 5-8 feet in front of the machine, then you should be able to ride the machine out of the hole you have created.