The closest I have is a rejection letter from Radio Shack HQ, I received as a kid, maybe around age 12. I'd spent many hours ogling parts and gear in their stores, and practically memorized their catalogs. So I was a big fan, and I'd written to their headquarters, proposing that I would write a hobby computers&electronics book, in the vein of some of the Forrest Mims projects articles I'd read. (With the difference being that I had almost no knowledge worth sharing.) I got back a polite letter, on Radio Shack stationery, not mentioning that I was obviously just a kid, and saying that they didn't wish to develop a hobby book, but if I developed it otherwise, they'd be happy to review a copy off the press. I had my first rejection letter framed for a while, but lost the original during a very lean move right after grad school, and now I only have a scan of it.
https://hackaday.com/2018/12/14/retrotechtacular-remembering...