HBO is going to mine every ounce of blood from the franchise. I'd be surprised if even half of those shows sees the light of day.
There are 3 super simple Knight of the 7 Kingdoms stories so far. Maybe enough per book for some standalone movies but turning one of those books into a 10 episode season is going to a stretch worthy of HotD season 2.
I'm not sure what they're thinking with 1000 Ships. The story of Nymeria and her 1000 ships is barely a footnote in the books. So I supposed HBO execs already order 3 seasons
Aegon's Conquest might have some hope, but that ground has been covered. Nine Voyages could also be good, but are the casuals showing up to watch the Sea Snake sail the Narrow Sea without his wife or the dragons