If you take a clip, edit it 1 sec in on each end so the in and out point are one second in and out, then chop the clip in half and append the out point to the in point then put a 2 second xdissolve on it, it would loop seemlesly. It would have to be a subroutine that automates the proccess but it can be done in QT so it could be programmed to automatically do it.

Christian