try Mik @ Soundlogic...
www.ramona.com/soundlogic
homie is dope, he hooked me up with and s950 before, and like 6 memory expansion boards for s950's...
he knows whats up bigtime and makes his own parts for some of these old machines... i know he used to have the Marion Systems SCSI board on his price list for around the same price as RogerLinnDesigns... maybe he has one available, or maybe by now he has figured out his own SCSI board for the 60... i only met the dude once, he runs soundlogic by himself it seemed, but he definitely knew what he was doing when it came to music and electronics... by the way, if i remember correctly everything he has is backed by a lifetime warranty... its worth a phonecall to see if he can help you, be honest with him about your situation and see what he says...
good luck...