While updating the wiki article on the 4004, I came across an interesting claim by Ted Hoff, who stated the idea of using a general-purpose CPU in a calculator came to him due to a minicomputer that had been donated to Stanford by the UK company Plessey.
I'm at a loss as to what this might be... I know Plessey had a range of realtime machines used for telephone exchanges and the Linesman radar system (rather unsuccessfully) but these were mainframe sized and I cannot find a hint of a mini.
I suppose this could be any old mini that Plessey bought and donated, but it seems less likely that Hoff would refer to it that way, if AT&T donated a PDP-11 to Stanford someone talking about it later would likely refer to it as "a dec mini".