Fascinating history, many thanks. One model I don't see mentioned is the single play SP20B, which I owned for a few years in my youth, before replacing with a gently used Pioneer PL-12D. An Autoslim derivation, it was similar to the 40B less some of its changer bits. I have mixed feelings about my time with this unit. On one hand, I whiled away many happy hours with it, listening to early prog-rock. On the other, it was a rumbly beast, with an inadequate arm lift and severely warped platter, and the plastic base resonated horribly.
I found a pic in the Allied Radio catalog archive, inexplicably with long spindle:
http://www.alliedcatalogs.com/html/1971-300/hr068.html.
I always assumed that since mine was a "B," there must have been a prior version, but don't really know.
These days, in addition to several manual decks, I own an SL-95B a friend gave me a few years back. After some work, it functions acceptably, except for a nagging issue if not shutting off properly after playing 45s with the fat spindle. A project for another day...
Thanks again!
Mike