So I was looking at the System 7 source code, when I saw this Makefile. (Surrounding it is the dbLite, the PB Duo 210; SuperMario, a universal 68k ROM; and a universal RISC ROM.)

What's interesting is the mention of DSPs - and the tier indicates a full-sized LC AV Mac? It was in development since '92, at least, in parallel with the Power Macs.