Sometimes people would *call* the NeXT machines "Multi-Processor" because of the standard inclusion of a Motorola 56000 DSP but obviously that doesn't count. (There was also the i860 "NeXTdimension" graphics board option, but likewise, no dice.) Beyond that, well, I certainly haven't seen any credible evidence that a multi-CPU 680x0 NeXT machine ever existed.
Brothers are always wrong. They're even worse than sisters.