I put in my proposed outline for my latest GURPS book. It's drawing from my DF gaming experience, naturally, but also from my prior fantasy campaign. We'll see if gets accepted. I know SJG is okay with me as a writer, but I don't always offer to write things they need or can slot into a schedule.
Hopefully this would be something I could see in PDF in 2019 - 2018 is just unreasonable at this point, as it's October already. You can't fritter away 9 1/3 months of the year and expect to get a book in that year.