Add Feedback to Layers / Add Feedback to Scene nodes

As discussed with @jstrecker at Feedback Layers or Scene without Image conversion ?

These nodes would input a list of layers / 3D objects instead of an image. As you fed in a series of layer/object lists into the node over time, it would store them up in the node and use them to compute the feedback. The node would output a grouped layer/object to be passed to Render Layer/Scene to Window. This would contain the most recent layers/objects plus progressively faded-out versions of the previous layers/objects. It would be more computation-heavy than the first option, but would provide correct results for layers / objects beyond the borders.

Opened for voting.

That seems more like a form of queueing and object replication, as described. Is that a fair assessment?

I think so. The node would be queueing up a history of objects. The overall effect would be of object replication (assuming you fed in the same object(s) repeatedly over time), with opacity decreasing from newest to oldest in the queue.