On page  252 of Meltzer's Mark Twain Himself there are
a pair of cartoons "From the Nature Faker's Gallery"
representing Mark Twain crossed with John D. Rockefeller.
"John D. Twain" shows Mark Twain with Rockefeller's bald head,
"Mark Rockefeller" shows Rockefeller with Mark Twain's
bushy mane.  Is it possible these were the images you were
thinking of?

Dave Thomson