Or maybe an approach to build one inside Reason using a few tools?
The convolver, such as in Dehumaniser 2 and Dehumaniser Simple Monsters, scrubs through the sample based on amplitude.
Here is Simple Monsters:
All of the Krotos plugins are currently on sale. I'm thinking of picking up Simple Monsters just for this. Dehumaniser 2 has always been on my list, but I achieve most of what I want using chains of other plugins I really like. What I am missing is the convolver.