[sillywalk]

> non-shared memory multiprocessor setups

It's not really comparable to the other examples you cite - the ncube/transputer/connection machine, in that it was programmed conventionally, not requiring a special parallel language, but Tandem's NonStop was this, starting in ~1976 or 1977. Loosely coupled, shared-nothing processors, communicating with messages over a pair of high-speed inter-processor busses. It was certainly a niche product, but not a dud. It's still around having been ported from a proprietary stack-machine to MIPS to Itanium to X86.

EDIT: I suppose it can be compared to a Single System Image cluster.