I made this from some 1" aluminum tubing and 90° angles and some slightly larger square punched steel. Bolts together. The crank is from a medium weight strap clamp. Total wt is 4lbs, max length 15". The original guy quit making them. There maybe another commercial version >$200 and twice as heavy. Guessing my parts were about $50 or less.
Here are the pictures:
Packed up in a couple cases I made. Obviously needs to be accessible from either side in case of a drop.
Showing the parts. The short Au tube is the middle, so the packed length can be minimized. The Au angles sandwich the 3 tubes and provide rigidity. The crank is permanently bolted to the steel square tube. The foot is also steel with some old tire treads attached. You might get by with something smaller, but I wanted it to work in sand if necessary.
Assembled, ~38" lift
Detail of the crank head. I wanted to push down to lift and maximize the lift height, so the crank needed to be on the opposite side with the strap running up and over. A couple pins and bends of the square steel pipe to keep it smooth. The crank is bolted to the steel with elevater bolts, top one to not interfere with the strap, and the bottom to allow the Au tube to slide in. If you have a welder that would have been easier. I ground the one bolt to maximize the strap capacity.
To maximize the lift, you can't let the strap double too much in the crank, just enough to get a good anchor. I have a loop and cam lock for attaching to the bike and eliminate slack in the lift strap before jacking.
In action, Hopefully it will display and play: