I wouldn't get your hopes up for a production run of anything 9000-related. I got my HIL converter from another hobbyist, it's a third-party item, and I'm pretty sure it was manufactured in the mid- to late '90s, when those machines might still have been out in the field somewhere. You'd be better off either trying to find another hobbyist with a spare or trying to hack something up with an Arduino or something than waiting for anybody to do a production run of the things.
Computers: Amiga 1200, DEC VAXStation 4000/60, DEC MicroPDP-11/73
Synthesizers: Roland JX-10/D-50/MT-32/SC-55k, Ensoniq SQ-80/Mirage, Yamaha DX7/V-50/FB-01/SY22, Korg DW-8000/MS-20 Mini/ARP Odyssey/M1/03-RW, E-mu Emax HD/Proteus/2, Rhodes Chroma Polaris
Synthesizers: Roland JX-10/D-50/MT-32/SC-55k, Ensoniq SQ-80/Mirage, Yamaha DX7/V-50/FB-01/SY22, Korg DW-8000/MS-20 Mini/ARP Odyssey/M1/03-RW, E-mu Emax HD/Proteus/2, Rhodes Chroma Polaris