David Carr, the prominent journalist who died earlier this year, wrote in one of his final columns: "Contrast that with Verizon, whose efforts to dip a toe into publishing turned out to be all thumbs." Mixed metaphors are usually errors, In this case, however, Carr used the device intentionally for effect.
"Faded Dinosaurs and Closed Puppies: More Mixed and Mashed Metaphors,"
Word Ways: Vol. 48
, Article 4.
Available at: http://digitalcommons.butler.edu/wordways/vol48/iss2/4