12745 HP-IB Adapter

So last week I did a rather insane 3000km road trip that had me travel through four states (Washington, Oregon, Idaho and Montanna) and over an international line to pick up a "pack-loading HP disk drive". It turned out to be a rather nice condition 7925B with a 13037C controller in the cabinet. It has the usual nasty foam you gotta remove and replace but otherwise it's extremely clean inside and out and powered up trouble-free. Unfortunately I didn't receive any 13356A packs with it, nor did I receive the critical component I needed: the 12745 HP-IB adapter kit. I don't actually own any HP minis unless you include the PA-RISC HP9000 D350 but I have a number of machines that will support mass storage over GPIB/HP-IB, including a Silicon Graphics machine. Anyways while I found all the documentation I needed for the drive, controller and adapter and there's that one pack on ebay for a less-than-modest $350 I cannot find even a hint of anyone who has a spare 12745 kit for sale. Was this an uncommon addon or am I just not looking in the right places? -John