The AY8930 Enhanced Programmable Sound Generator is a very rare Microchip (who bought GI) version of the AY-3-8910. It includes better frequency range, noise, PWM and independent control of the envelope for each channel.
I was lucky to find a stash of those chips and will soon try them on my AY-3-8910/YM2149F protoboard to see if they work and experiment with them, then for a future addition to chipsounds.
As far as the interwebs are concerned it only has been used in one PC card (Covox Sound Master+) and one game (Where in Time is Carmen Sandiego). So my job will be to hack dosbox into spewing the register writes it sends to this chip and I'll make a render using my board (the usual stuff).
Since I have now too many AY8930's to care, if you are interested in upgrading your MSX, ST or whatever (untested), this might be your chance, since I will put a few of these rare babies on sale after they are tested.