MIPS-based DECstations/DECservers
Some of the MIPS Rx000-based DECstations/servers were quite impressive machines and ran Ultrix, a fairly vanilla BSD Unix variant. The only problem was that they were introduced late in the game, and DEC salespeople would rather shoot themselves than sell you one. I remember explicitly asking for a DECstation 5000 quote, and then getting a visit from the DEC rep pushing VAXstations.