I've also spent a little bit of time revisiting vintage synthesizers still. That said, among the libraries I have are soundfonts based on the Emu Proteus ROMplers from the early 90s. Unfortunately, these soundfonts, while official (courtesy of Digital Sound Factory), only cover two thirds of all the factory presets of the standard Proteus modules, and none of the XR presets are represented.
And then the other day it occured to me: I could try my best at recreating those patches mysef in Kontakt. The XR variants had no new samples or waveforms, anyway, meaning I should have all the foundations I'd need to make the missing patches.
Unfortunately, there will be some caveats to this project should I try to pursue it:
1. While I used to have a Proteus 3 XR (and thankfully was able to get a SysEx dump of its factory patches then), currently, I have none of the modules. What this means is that I will not be able to confirm how faithful the patches sound to the real deal on my own, which can especially be a problem when it comes to envelope times and modulation amounts.
2. Any distribution of the samples would violate DSF's terms of sale. I did just think of the possibility of distributing just the new programs and not the samples, though: while inconvenient for end users, it should hopefully get past the reasoning for the DSF soundfonts not being allowed to be resold, though I'd need to confirm this.
3. It would be very time consuming, partially for the reason of the first point.
So, for any other vintage synthesizer nuts out there: is there interest in this idea? If there are interested people, would anyone be owners of the original hardware? If yes to both, feel free to reach out to me, either through my contact page or via the comments of this post.