mneme suggested I write a different sort of book, not a novel, but a book of advice about adapting scenarios and other material for gaming purposes. I don't know if there'd be interest or if it'd sell, but... yeah, I've certainly been doing a lot of that.
Most recently, I did a good job of running one of the Kindaichi mysteries for ebartley. There was a bit of illusionism, which I revealed after the scenario was concluded -- there was one place where I did the GM equivalent of "pick a card" while ensuring that it would be the card I wanted. But, the thing is, I could eyeball the manga and know it would work for ebartley (at least once I'd spent a weekend thoroughly reviewing everything and taking copious notes, which were more mnemonic than anything else).
I'm currently trying to write up how I did something similar with Jim Butcher's Fool Moon. Unlike the Kindaichi manga, it did not follow the source material perfectly, nor had I expected it to do so.
Well, whether there's a book's worth of stuff there, there's certainly an sf convention panel's worth of material.