It would be more of an anti-flexion exercise. Still useful though. You could add in a DB or KB "pulse" so to speak on lunges, lateral lunges or goblet squats. You would lower down, then bring the weigth forward, further from your body, hold it for a second or two, bring it back, and finish the rep. Great core and stability training. Like Tony G. Here: http://www.youtube.com/watch?v=uBiggVkfX6k
The free weight equivalent for pallof presses would be a plank that has some pulling forces in it. Like plank DB rows for one. If you can get some block to do the plank on, you can do full-range DB rows while in the position, giving your body a huge rotational force to counteract with. Or bands work great too.