I actually stopped reading after Ultimates 2 (mostly due to relocating and not knowing anyone that read them in my new area), so I wasn't even sure if they had introduced Thanos in the Ultimates line yet or not.
As far as the Armor Wars comment earlier, I would love that but it would have to be an Iron Man only movie. Though they need to introduce a LOT mroe armored villains before something like that would start to make much sense.