Pixelmapping - "Remove Unused Content" option

Would it be possible to have an option to remove all unused pixelmap content?
I have a shed load of clips I use. I load them all into my show, as I want to experiment and see what looks good on my current rig.
Then, when I've finished programming, I'm left with a whole bunch of stuff I've not used.
It would be great to have a "remove unused content" button to save a lot of time, similar to the old "remove unused fixtures" option in Hog 3.