For anyone who's interested, i remember reading in the ES forums once about exactly how this works - in a field of debris, when the last piece is collected, the whole field respawns as collectible pieces again IF you are OOS at that moment. If i remember, this actually wasn't in the original release of TC, but was somehow introduced somewhere around the 2.0 patch. I haven't used it yet, as i haven't started playing TC until now... i might use it in some games, if i want a faster buildup - but most likely not in my first game of TC.
I suspect that the exploit might be patched out in TC 3.2, and it's probably not in AP at all, based on one of Cycrow's comments.
(if you plan to use this, i also remember reading that jumping out of the system can make the collectible pieces start to reaggregate right away, so it's better to fly to the gate.)
in Reunion, I did mine out a lot of the nividium rubble - but it depletes and is gone forever then, even OOS.
One thing I found while doing this is that in the early game, you can easily end up with money that you can't easily spend, because your race ranks aren't high enough.
on X2 - the X game i've spent the most time in so far - I don't think that ES really finished the game, there were a lot of scripts for it that felt like they should have been there initially, instead of ES letting the modders make them (to list a few : Trader Mk 3, the SDS script by Kor'ah which became CLS Mk 1, the BPH script that became CAG, there are plenty more even just in the signed bonus pack.)