I have been working with two famous and critically respected authors in my MFA program who have been more than enthusiastic about my quirky literary manuscript. One of them said that "it was simply amazing and I need to find an agent immediately and get this thing published!" The other teacher says he has no doubt that this will be on the shelf. Should I mention this in my query letter? I must say that I am not confident about the this book being marketable as it is basically a novella at 40,000 words, although my teacher calls it a novel and it is a bit unusual with regards to language and form. I wrote it because it was what I needed to write and when I began I wasn't thinking about publication although now I am very excited about the prospect! Should I send it out as is or try to make it longer or a bit more traditional?
Addressing the issues one-by-one:
(1) You have two famous and critically-respected authors in your MFA program? Seriously? Are you in school in Iowa?
(2) OK, being serious, having an author's recommendation in your query letter as a sentence or two is almost never bad, provided that author was not self-published, because then it doesn't count. So yes, you should put that in your query letter. Specifically, you should put the good things they said about your manuscript in the query letter, not the fact that they said it should be published.
(3) 40K is a novella. You can send it out, but it will probably get knocked out of the running on that alone. On the other hand, you may get lucky. If you're prepared for a slew of rejections, you can give it a shot. Most published authors have rejections from other manuscripts under their belt before they get an acceptance.