I know very little about the FDE mags outside of internet warrior legend, but someone on another forum I frequent posted these out on flea bay.
The keywords (and generally everything else) is pretty cheesy, but I thought I would put it out here in case any of you guys are looking for one. Very pricey I think, but he has a "make offer" button.
I have no affiliation with the seller. As someone with a fairly plain vanilla Glock collection, I would love to add something unique to the herd, but there are other pieces way in front of the FDE mags.