I don't ever see the core franchise going international... Fallout's canon provides for an entire post-nuclear world, but the setting, the heart of it, is America. Americana and American perceptions of the atomic age very much drive the series' themes and aesthetics, and a lot of us agree that taking things to the East Coast, or even just the midwest (with Tactics), was a misstep. That said, a series of spinoffs could prove quite interesting. Fallout: Wasted Lands, or something along those lines. I'd propose Canada and Australia as two great places to start. Australia has all the potential to be a harsher, more self-contained version of the American wastes, with bigger, badder critters, even harsher environs, a more strongly emphasized survivalist element, and a healthy dose of Mad Max. Canada... Canada is such a no-brainer it's almost cheating. There's enough of a military presence due to the annexation and enough shared geopolitical issues with the U.S. that you'd get to keep a lot of the more beloved/familiar plot elements, and it's the overland supply line/support corridor between the lower 48 and the Alaskan front. The major military tech that crops up in other American settings wouldn't be present here in such concentrations, though, as taking Canada wasn't much of a challenge and the materials were in demand elsewhere. I think it'd have a generally more run-down feeling, more of a wooded frontier. Sort of like if The Den and Modoc were stretched over an entire continent.