Well, its only partially what you are looking for, but you can image your entire phone using my tool: http://talk.maemo.org/showthread.php?t=58633
Then, if you screw things up, you can reflash back to that image, and not have to reinstall anything or change any settings.

It won't help with "reflash to improve performance", because you are restoring to the -exact- state that you backed it up in.