Alternatively, they're scouting now - but Faulks changes the game, I think, in the same way that Craig changed the casting of Bond. Just as some Serious Actors might have considered Bond beneath them pre-Craig, I think lots of writers who might have seemed out of reach might now be rather keener to have a massive sales boost and a run up the Thames with a blonde. It's not just a moderate commercial sucess, but a massive one, so even the biggest-selling writers in the world must now be at least a possibility.
True; they won't be hoping for quite the same impact as DMC, but I'm sure they'll want to keep up the momentum as much as they can, and sadly I'd guess that they'd do that by getting a new man in. 'Amazing award winning writer writes Bond' is a better headline than 'that guy who writes Bond at the moment is writing another Bond' sadly.
If they were going for a new series or perhaps lots of one offs, I'd say Higson would stand a greater chance.
But as you say, he might be writing it right now, so I'm talking into my hat.
But yeah; War Bond gets my vote. Similar enough to the Bond we all love (secret agent, globe trotting, drives Bentley etc.) but different enough from Fleming's books to make it worth doing. I'm always in two minds about doing new Bond books- it was Fleming's writing that made them good, not Bond himself; so there's no real point in doing new ones unless you add something new or do a Fleming impression- and I don't like impressions.
And perhaps it's because I'm in Indiana Jones mood at the moment, but who wouldn't want to read James Bond vs. the Nazis?