Has anyone experimented with panning and zooming in 1080p and downscaling to 720p with decent results? How far could you go?

I shot a short 1080p action sequence with a locked-down 5DmkII, then used AE to crop a 720p frame and panned all over to give it the hand-held look: the trick is creating motion-blur that matches the move. Zooming is trickier, and I cheated by comping a tight-shot into my one big zoom shot. I'd guess you could zoom-in up to 2x using AE before anyone started to notice the degradation.

Untitled on Vimeo
...and no, I barely got an honorable mention in the contest...8-(

Thanks, Drew. You gave me a place to start.