Terrible name. And a globe-trotting fallout game?!
How about a fallout game where the entire game is spend in and around the vault? It'll be a realistically-proportioned vault with a 1000 person capacity, all manners of life support are rendered in details, with equipment failures and tunneling mutant invasions, factional conflicts, etc. etc. It'd a survival simulation.
It could be a dlc or an expansion to FO3 or New vegas. Or a mod even.