Some discussion of this idea has been taking place in an
older thread in Tips & Tricks, but I wanted to refine/update my suggestion here on my official "wish list". :)
The feature I'd like to see would allow you to grab clips from any of your cams or outputs, and save them in a media slot.
You'd hit a little record button on any empty media slot, choose the source (cams 1-4, outputs 1-8) , and it would start recording until you hit stop. Then you could use it like any other piece of media.
This, IMHO, would be a powerful feature, allowing you to, among other things, perform and capture complicated mixes on the fly, which you can then reuse right away if you want, even as part of another clip you capture (which itself could end up as part of another clip and so on...). In the audio world, this is similar to "bouncing" or "mixing down" multiple tracks into one, and it's very handy. :) For instance if you run out of tracks (layers) you bounce them down to one track and now the rest of your tracks are free.
There are some other examples of how you might use this feature in the
other thread.