I had been thinking along these lines myself - I may ask for one of these for X-mas. While I generally have no trouble picking up the GSA, I did run into some difficulty on my trip to Wyoming.
I was riding some cow-paths (the GPS was convinced they were roads!) and got into some loose rock on a fairly steep uphill section. I found myself heading off to the side of the two-track, into the thick sagebrush. I over-corrected coming back onto the road and went through the right side track I had been riding and into the middle hump between the two tracks. I hit a large rock that was hidden by the sagebrush in the middle of the trail and took an unplanned dive from the bike.
This was a low speed launch (~15mph) but I cracked a rib on landing. My toes were pointed, however, so I did get straight 8's except for a 6 from the Ukrainian judge
I was alone and on a steep, loose rock hill. My rib was making it difficult to breath but this was not much of a detriment, as I was just over 8000 ft elevation and there wasn't much air to breath anyhow. It took several tries before I was able to get the GSA 'out of bed'. I was miles from any possible assistance.
This jack would have been a VERY welcomed accesory in this situation. YMMV
Thanks for bringing this to my attention!