During the online Resistance Exercise Conference, there was a short segment where a trainer (Skyler Tanner) did a demo showing how you could use a Medex leg extension machine to do hip thrusts. He suggested that the fall off cam on the leg extension addressed the issue that Bill DeSimone had with the hip thrust exercise, namely that when done with a barbell, the resistance curve is all wrong. I wonder if that might have some utility for some of you?
Also, I see that Rogers has a machine in the Pendulum line called a Reverse Glute Ham machine. The movement reminds me of what happens in the Nautilus Hip and Back, except you extend both legs at the same time, rather than alternating legs.
Then there is also the Gluteator, which seems to be gaining some popularity.