I know that 5 Ohio Players' albums (Ecstasy, Skin Tight, Fire, Honey, Contradiction) from this era (72-76) were released in Quad..
..but could it be that the two OP albums ("Pain" and "Pleasure") from the period before their 1st Quad album, were also remixed but were never released?
I only ask as I was playing through 5 of the albums of this period (the 5 from Pain to Contradiction in stereo, skipping the two quads released on DTS CD) and they ALL sounded absolutely wonderful when played back through ProLogic..!!
Just a coincidence as they're all produced in a similar way that PLII really really works well with?
Or could all the CDs of these albums be from quad/sq sources?