Rescale to fit frame

I'm editing a new showreel using material with very various sizes and aspect ratios so there's a lot of Pan and Zoom filter to get everything fit the same space.
I'm guessing it's a quite common task to rescale material to fit so I would like a feature that rescales the material to fit your project size, scaling so either height or width fills project width/height.
Best solution probably is having a filter for this?

A center crop filter is already on the MLT roadmap:
http://www.mltframework.org/twiki/bin/view/MLT/ToDo