In the words of the modding team, 'Visiting a totally new setting allows for us to explore totally new cultures which have not homogenized with their American counterparts. If you had any doubt that the cocktail of retro-future nationalism and classism would stick elsewhere, well here's Fallout: London to settle it. Fallout sometimes feels inseparable from mid-century delusions of American Exceptionalism and corporate tomfoolery.
Other large modding projects are already in the works for bringing Fallout 4 to Seattle and Miami, just off the top of my head.
Honestly, it is neat to see a modding team looking outside the US. Here's the trailer for Fallout: London in all its very un-American glory. There's no release date yet, and it's certainly looking like there will be plenty of infighting between its new, British factions. Things look just as irradiated, divided, and gritty as you'd expect from a major Fallout 4 mod project. Fallout: London is planning to take players to see how the war affected things in the UK. Yet another giant Fallout 4 modding project has released a trailer for an ambitious expansion-sized campaign.