In response to the question if anyone has done work on the trickster figure
in MT: sho' nuff.  So's not to appear coy or falsely modest, I have.  My
1988
book, _Twain's Heroes, Twain's Worlds_ (UPenn Press), explores the
folkloric,
mythological origins of heroes in Twain's fiction and the explosion which
results when Twain deposits these supernatural creatures into an
historically
determined reality.  Despite the heroes' remarkable powers, history wins;
one
can see Twain's fiction as an on-going attempt to find a super-man capable
of
transcending history, and the on-going pattern of defeat.  Not too many
folks
have picked up this interpretive flag since, but a few have.  The Humanities
Citation Index might be a good way to trace where the argument has gone
since
the publication of my book.