In the February 1979 Kickshaws, the late R. Robinson Rowe proposed Word Ladders which successfully reverse the letters of a given word. To judge from the discussion there, he actually found only two examples of four-letter reversals.
"Reversible Word Ladders,"
Word Ways: Vol. 13
, Article 16.
Available at: http://digitalcommons.butler.edu/wordways/vol13/iss2/16