Poor old IBM and OS2. If they hadn't have gone their seperate ways from MS, who knows what might have happened? BeOs, if I remember correctly, was designed in part by ex Amiga guru Dave Haynie. The 'Next' machines looked pretty awsome for their time. A trip to Google is definitely in order for more info.
Didn't the Atari Jaguar have two 32 bit risc chips, with a plain 68000 running as some kind of control chip? They certainly advertised it as a "64 bit" console. More research needed to refresh my ailing memory...