Given the sorry state of affairs for Necromunda rules/books/encyclopedia sets, I'm actually shocked they're not dragging this out for another series of 6 books.
Dragging things out for 6+ books is still very much on the table, isn't it?
1) Book of the Outlands already had nomad fleas and orlock vehicles (and squat gang missing unique vehicles)
2) escher + goliath
After that I could easily see:
3) cawdor + van saar
4) delaque + the missing squat unique vehicles
5) enforcers + cults
6) scavvies and/or redesigned ratskins, if those are coming.
And of course that's not even counting the ash wastes rulebook that any reasonable person would think would have most/all of the vehicle rules and stats in it, lol.