I am also interested in reproduction labels. I'm not a printing expert, but I've worked on a few projects with print houses. My ramblings follow.
I don't think anyone has posted this link yet, but there are quite a few variations of PET labels out there:
http://www.6502.org/users/sjgray/computer/petlabels/
I think it boils down to a few basic "styles" though.
The basics start with single-color print on foil (no laminate) and single-color print on white (thick textured laminate). Then there are some oddities like print color changes. It also looks like some of them are a brushed foil background instead of the shiny versions. There are also versions of the decals that have a thicker plastic (?) border around the edge.
There also appear to be various shapes and sizes, specifically (at least) two different heights. Some of them also appear to be more square than trapezoidal (but this might be due to the camera angles).
I bring this up as it would be nice to figure out some basic styles that are similar from a reproduction perspective. From prior experience using print shops, we'd want to distill them down to a "style of sticker" and then figure out how to print each style (with a vendor familiar with this). Theoretically a print shop could change the artwork (as long as we aren't forced to get screens cut or something like that) and apply multiple versions of artwork to stickers that are of similar construction. Limiting the styles might help in lowering setup costs and things of that nature. Quantity would also bring prices down.
I think the easiest is the foil-backed thin sticker. I'd think we could probably get a decent looking result with laser printing on a foil colored vinyl back. Second easiest would be the textured finish laminated version printed on white. The ones that would concern me are any that have the 3D border.
That said, it might boil down to four or six variations. Foil backed in both heights, textured vinyl with a white back in both heights, and maybe the brushed foil back as a wildcard? Once we had that basic stuff down, running different artwork on top might be easy and basic to change.
Does anyone have a print shop they've worked with, or know anyone in the print industry that might be able to assist? Bonus points if they are familiar with adhesive vinyls, laminates and things of that nature.
I could make some phone calls, but a lot of times it's easier for smaller runs if you have an "in" somewhere.
Edit: We could also consider making them "better" than the originals instead of close/perfect reproductions. One thought would be a gloss laminate over the printing on the foil version of the sticker.