I just received word that Artist Alec Stevens’ graphic novel on Sadhu Sundar Singh is in print and available through Calvary Comics.
Stevens sends this word because of a post Lars wrote in May which mentioned Singh. On our old blog, Lars wrote:

I’m a long-time member of the New York C.S. Lewis Society. In January, 1991, the society’s Bulletin published an article by Lindskoog which appears to be an early version of the “Golden Chain” piece. It was titled, “C.S. Lewis and Sadhu Sundar Singh.” A comparative reading shows that the material is very similar, though much of it has been rearranged. A further difference is that this (apparent) early version features no mention of the Visions book in relation to The Great Divorce.
In response to that article, I wrote a letter to the Bulletin editor. That letter was published in the January 1992 issue (the delay in Bulletin releases in those days was something of an embarrassment). A portion of my letter is reproduced below:

I enjoyed the article [by Kathryn Lindskoog…] on Sadhu Sundar Singh as the original of Lewis’ “Sura” in That Hideous Strength.

I recently picked up a booklet I have owned for many years but never read before, Visions of Sadhu Sundar Singh of India. It was originally published in 1926, and contains a series of teachings on life after death which the Sadhu claimed were revealed to him during ecstatic experiences. He tells of conversations with angels and blessed spirits, and direct visions of heaven and hell and an “intermediate state” between them.
I was intrigued by some apparent similarities between the visions in this book and the scenes in The Great Divorce. The Sadhu pictures the intermediate state as a place where the majority of human souls are met by angels and spirits of saints [and] are given many opportunities and encouragements to believe in Christ and go on to higher and higher states of grace….
…I can’t help wondering whether there is any evidence of Lewis ever reading it. It could have been a spark for his artistic imagination….

I expressed my devout skepticism as regards “intermediate states,” and closed with publication information on the edition of the Visions I owned (which, as it happened, was published by Osterhus Publishing, a small press/bookstore within walking distance of my present home).