I can't speak to Johnny fitting in your harness, but I just tried to slip it into the hole of my jaguar, through the back, and it fits. Now, it's too big to use the o-ring, but can still be used if just pushed through the hole. I would imagine for the Johnny, being so big, the commando might be the best suited for this but I am not sure..As for other ball-less toys, I know I love using the mustang as it's about 1 1/2 inches in girth and I think 7 inches long. Johnny is about 1 3/4 inches think, if not a tad more, so you could also try Buck from Vixskin, Raquel ( a tad smaller), or tantus's O2 Mikey if you are looking for girth. Hope that helps
Enjoy as the Johnny is amazing.