Hi Alex,

I did something similar yesterday in Oulu Dance Hack, using a feedback loop through an Effect Mixer with a Video Delay. Super simple, but quite difficult to imagine the results.

The Video Fader controls how much of the image is fed back into the system. Zero gives you an infinite buffer, 3 or 4 gives a long fade out. 
Its particularly effective if you can control which bits of the image get fed into the system. I was using lighting in a dark space, but you can use something like Difference to split off part of the image and get it looping, then combine it back with the initial feed with an Alpha Mask or something similar.