OK I have a deal for the whole shebang, pending working out a time/place to meet. If that falls through I'll post back here in a week or so.
Those negative carriers were gathered over quite a stretch of time on ebay, a few years ago. I think if you're patient you'll eventually find any given carrier you're looking for there. You have to be extra-super patient to get them at sane prices like I did, though.
Yes, I owned and resold a few of the computerized color heads along the way and the same line of reasoning is why I kept the newer manual one! I got them all running and bulletproof, but all it would take is one IC failure and the thing is unusable until it's repaired. Obscure detail note: this 45S head has the newer 4x5 mixing chamber (without the feedback loop electrical connection), while the 35mm box is the older style (which works just fine in the newer head, with nothing plugged in to the connector.) You can use an older mixing box in all heads, but the newer boxes will only work in the newer head.