While Jumps and Swings do seem mechanically similar, I have a hard time imagining that jumping would strengthen your back any more than a Pistol will. If your concern is regressing in Swings because your lower back gets weaker, I'd opt for Steve's suggestion or the 1-leg DL. Also the 1-leg glute bridge is an excellent exercise in its own right.
You could potentially regress in Swings since those exercises don't have a large conditioning aspect however. Might be worthwhile to add in some basic Burpees (which, interestingly enough, do incorporate a jump!) just to maintain the edge.