ISO: I/O panel for Wangco ST-2222 (or similar) drive

Hi all -- Picked up a mostly complete Wangco ST-2222 drive recently. This is a removable pack drive with one fixed platter, nominally Diablo 30 / RK05 compatible in terms of interface, but uses IBM 5540-style packs. It's in good condition and I'd like to restore it and see if I can interface it to an RK11. The part I'm missing is the I/O panel -- on this particular model there was a breakout board that bolted to the rear of the rack the drive was mounted in (rather than being mounted to the back of the drive), and it contained some buffers, level shifters, drive select logic, and the actual interface connectors. There were two variants of this -- 301062 was the Diablo 30/31 style (with the big Winchester blocks) and 301291 had a more generic interface with what looks like centronics-style connectors. (You can see assembly drawings of them in the schematic here: http://bitsavers.org/pdf/wangco/301462-002_Super_Series_Magnetic_Disk_Opera…, pages 55 and 69). I figure it's a long shot, but does anyone have one of these two boards going spare, or have a similar drive (others in the ST family share the same panel, it seems) that is in unrestorable/parts-donor condition they could steal one from? Thanks, Josh