As much as I would love Contact Harvest to be made into a film, I wouldn't say, "no", to a Kilo-Five Trilogy adaptation.
you know, if they fixed some of the crap we got in that trilogy, I wouldn't be opposed. Like if they dropped the "Halsey is Space Hitler" vibe the story would be 1000% better. I mean she was an awful person, but the book made her out to be this solitary bad actor within the bowels of ONI, which we all know is simply not true.
My vote would be for a Contact Harvest movie though. Heck I want a game about Contact Harvest. Call it "Halo: First Contact" so that it can be differentiated from the book slightly.