David - 2013-11-18

This does take advantage of cache already for the texture previews. But for the export this would not be optimal as your export size is not completely know or in context

.As well is very CPU intensive and edits would need to cause down stream renders witch would kill the GUI as the Re-Rendering of the downstreams would use the CPU up.

Now if the Rendering was more threaded we may be able to control this a bit more and have a constant render going while you edit / make changes to decrease the export time.