Here are the only references which I could locate to anything resembling a claim in print that Smith was 'homosexual' or 'gay' through a Google Books search in chronological order:
"What we have here (in Secret Mark) is a nice ironic gay joke at the expense of all of the self-important scholars who not only miss the irony, but believe that this alleged piece of gospel comes to us in the first-known letter of the great Clement of Alexandria." [Donald Akenson Saint Saul p 88 and Surpassing wonder: the Invention of the Bible and the Talmuds p. 597 (the same passage is reused twice)] Bart Ehrman among others interprets Akenson's comments as inferring that Smith was gay. (Lost Christianities p. 267)
A list from Google Books of references, collaborations etc. between Akenson and Neusner here.
"A book that did not get the attention it deserved this past year is Stephen Carlson's The Gospel Hoax: Morton Smith's Invention of Secret Mark. Morton Smith was a distinguished professor at Columbia University and a not-so-closeted homosexual." (no footnote) [First Things: a monthly journal of religion and public life, Issues 173-177 p. 74]
"Morton Smith was one of the most fascinating and gifted students of religion was the twentieth-century theologian ... he briefly became an episcopalian minister but decided that that life was not for him - possibly because he was gay, (no footnote) probably because his intensely questing mind was more suited to academia." [Melissa Katsoulis Literary Hoaxes: An Eye Opening History of Famous Frauds p. 264]
“Are you saying Smith not only forged the document,” I said in amazement, “but that he then wrote a 450-page scholarly book analyzing it?” “Yes,” Evans replied. “It's bizarre. Actually, if you really read his book, you'll find much of was filler, but I've met people who say, "I knew Morton Smith, and he was fully capable of doing such a thing.' I do think, though, that the question of his motive is the weakest part of the case. He himself was gay, which was a closely guarded secret in the 1950s. (no footnote) He had been denied tenure at Brown University and may have wanted to demonstrate his intellectual superiority by pulling off something like this.” Evans picked up Carlson's book and searched through it until he came to the quote he was looking for. “Carlson put it this way,” he said, reading:
[Smith] was denied tenure in 1955 at the university where he started his career. Smith was forty years old and might have been perceived as over-the-hill. A successful hoax could be exactly what Smith needed to prove to himself that he was smarter than his peers and might even jump start his career in the process.
Evans closed the book. “Who knows? I certainly can't divine someone's intentions,” he concluded. “But why he did it is a rather secondary question. The big issue is whether he did, indeed, write the text—and I believe the evidence is compelling that he did. [Lee Stroebel, the Case for the Historical Jesus Google Books did not provide page numbers]
A list from Google Books of references, books etc. which represent collaboration between Craig Evans, Jacob Neusner and Bruce Chilton here.
"It should also be pointed out that Morton Smith was homosexual, (no footnote) and that from 1941 on he spent several years in Jerusalem." [Jesus of Nazareth Paul Verhoeven, Rob Van Scheers p. 196]
Of course, you'd think by the way people throw out the whisper that - 'Smith was gay you know' - there would be some quotable source. There is none. However the fact that Chilton's article (basically a reprinting of his 2006 New York Sun piece) in a journal edited by Neusner speaks volumes here.
A list from Google Books of references, books which represent collaborations between Bruce Chilton and Jacob Neusner here.
