As you may know, I have worked with the autobiography for some time -
the Univ. of Wisconsin edition was the result of some of that work.  I
am now at (or trying to) work on a book that will focus on questions
related to the autobiography (I actually have the contract already -
again from Wisconsin Press).

While at the Project in April, I took the time to read through the full
spread of manuscripts that are in the autobiography file.  There is a lot!
Depending on how you count and what version of the typescripts you use,
there are some 2,500 pages of material.  There are also real questions
regarding which version of the typescript to use (there are often several
different versions with comments in the margins).  I don't want to get
too far along with an explanation here, but the project will be immense.
The Project will, I think, have a helluva time working through all that
material - although a lot of their work on the letters will be of
great help in setting the context.

I have thought that the full range of materials and manuscripts would
be a fine addition to any understanding of MT as well as a rather
nice snapshot of the 19th century.  I am also (I think) sure that such
an edition would be used more by scholars and Twain enthusiasts rather
than as classroom text.

But let me think on this some more and get back to you all....