This feature usually goes hand-in-hand with multithreaded downloading because the inherent nature is the same. This would require a change in the core of flashfxp (much of the same changes that multipart/threaded downloading and tabbed sessions do.. to be done correctly and efficiently). As such i would personally prefer it be added along with those features in the possible rewrite rather than what would almost certainly be a limited hack job to the current codebase (not to mention it would bring a wave of 'you did that why cant you do multi threaded downloading and tabs without reweite')
Anyways, i like the suggestion