Dear Ms. Dorman,
  I hazard some responses to  your questions --"Is there work out
there in which Mark Twain figures as a fictional character?  Has he
been imitated on the page as well as acted on the stage?  If so,
where?  What was the quality, what was the type of work?" -- in the
"Impersonations and Impersonators" section (pp.150-167) in my book
_Lighting Out for the Territory: Reflections on Mark Twain and
American Culture_ (Oxford UP, 1997).
All best,
Shelley Fisher Fishkin
--
Shelley  Fisher Fishkin
  Professor of English and Director of American Studies
Stanford University, rm.420  Bldg. 460
Stanford, CA 94305
(o) ph: 650-723-1804
[log in to unmask]