I have never seen fielders in positions that would hardly be recognisable as the "standard" positions, and probably for good reason. (I mean a positioning where a casual observer might have difficulty identifying who is playing which position.)
However, are there known (modern) instances where teams/coaches (competing on the highest levels) chose for a "radically" different field placement on specific occasions?
(Examples might be: 1) the third-baseman is placed in the outfield, or 2) the second-baseman is placed in the outfield, or 3) the right-fielder is placed between the third-baseman and the shortstop, or ...)