Is it possible to have one image loop sequence loaded and texture every object in the scene with this sequence but randomly shifted in time ?
Absolutely. And the plugin would also need to handle all the image sequence/video functionality natively (except for loading the actual image files... but stuff like finding a sequence etc...). And also need to completely mimic the image mapping node.My guess is that you would need access to the full uncompressed video all the time, which would not mean much for shorter clips but would add up pretty quick.
Now that you mention it Actually, I've had a few ideas for V2.0 in mind for ages now, and one of them is image sequence support.I guess that it would be possible to add such functionality to a plugin like InfiniMap with a conversion of the video to the wavelet format it uses.