The world’s greatest rejection letter. From the desk of Hunter S. Thompson?

When a magazine rejects some bit of prose you’ve submitted, the usual response is a politely-worded letter or your well-creased copy sent back to you without comment. In the case of young Mike Peterson (read his memory of it here), the rejection to his submission to Rolling Stone in 1971 is something else. Obviously penned by Hunter S. Thompson but signed by a ‘Yail Bloor III, Minister of Belle Lettre’, the letter is as incendiary as Raoul Duke ever wrote but with a nice P.S. to sweeten the bombast. Classic.

UPDATE: This appears to be a form rejection letter provided to Rolling Stone by Thompson.

A question has arisen about whether the letter is original or a form letter. It has been quoted multiple times on the Internet, and it turns out was cited in“Gonzo: The Life of Hunter S. Thompson” as something he provided the magazine as a prepackaged rejection letter. 
Here is the passage, from page 138, one of a series of anecdotes from former RS staffers, this from Charles Perry:
After ‘Fear and Loathing,’ people in Colorado were giving him stuff they’d written, thinking he could get them in ‘Rolling Stone.’ I was the poetry editor, and he sent me a package of poems from other people once, with a note that said, ‘I don’t know about this stuff. If you feel the same way, send it back with to them with this.’ He included a prepackaged rejection letter that said,

(full text of letter follows, including the reference to South Bend)

We actually sent it out to a few people, thinking they would appreciate it. One person took it to a lawyer and asked if he could sue us, and the lawyer said, ‘No, you don’t have a leg to stand on … but could I Xerox it?’”