Looking for direction in creating record from inventory detail/serial number record

I need a little help deciding on an approach, if you all have any ideas, I'd much appreciate any input - I've searched the forums pretty exhaustively, not to mention stackoverflow and whatever else my google fu would provide.

Situation - need to create a custom record (asset) when serial number subrecord is created. As many other folks I've noticed on here, we have a custom record for serialized assembly items we build, because the subrecord doesn't cut it - we need to attach things like calibration certificate pdf, store calibration data per item, etc. Apparently before my time we had a script created by a third party but they turned it off as it was duplicating the records. Also, from what I can tell by looking at the scripts, our process has changed somewhat since then.