InstaUp2Date/InstaDMG Cache after catalogs?

I was just curious if it would be possible/feasible to have a feature in InstaDMG/Up2Date that would allow images to be caches after processing a catalog. The idea is, the Vanilla image might not change much for a month or three, so why not cache the image after vanilla has been processed and then pick that cached image up on the next catalog file in the build chain. This would allow the time between builds to be a lot faster (with testing mainly in mind). Is this something that is on the roadmap and is it even possible? Thanks! Nate