Come to think about it, can anyone actually name a widely commercially-available multiprocessor+shared-memory Motorola 680x0 based machine? There are some mentions on the NetBSD mailing list of an obscure dual-68040 VME CPU board which does have an experimental port but doesn't have functional support for the second CPU. There are some really early/large multiprocessor 80386 based machines like the Sequent Symmetry, but I seriously can't find a Motorola equivalent.