Sorry to dredge this one back up, but an update.
I gave in to the craving to put a shiny new bb and Campy Centaur crank on it today. It looks awesome. But it no longer shifts into the big cog. I even tried resizing the chain. My only guess is that the new chainline killed the mojo that the old one had. So now I need to decide between new derailleur or new cassette+spacer. I really like the way the old suntour looks on this bike... I have a newer suntour xcm on my old MB-6, it would work, but not look nearly as cool. And looking cool is really what it's all about, right? Or is it the hokey pokey. I'm so confused...
I think an old Campy derailleur would look snazzy, but likely have the same issues. And way too poor for that. I have a couple of Shimano derailleurs that could be pressed into service, but I just don't like Shimano that much.
I'm open to suggestions, ideas, critcisms, etc.
I'll try to edit this post after my little one goes to sleep with a pic of the new setup.