How about a vault that is made with the technology of an old Ben and Jerry's ice cream factory? In the fallout of Vermont, the famous ice cream creators Ben and Jerry's constructed their own smaller vault away from the influence of Vault Tec. A smaller vault for the workers of Ben and Jerry's (as well as the owners) and their families, this vault is a more wholesome tale of a small group of Vermonters who went away in their vault so they can make ice cream in the new world. This vault has the best refrigeration and ice cream creating units. Ac blows through to create an outdoor Vermont atmosphere, and a large room has been terraformed to look like the winter snow covered forest of Vermont. Allowing vault dwellers to still be somewhat connected to nature on their breaks away from ice cream making. Very fall and winter Vermont themed vault.
Or how about a vault run by robots for robots? So maybe the vault would be redone to be very shiny and chrome. Pristine vault condition. But maybe in the back of the vault could be a room or two just heaped with bodies of the original vault dwellers (a bit of a secret horror themed vault).
Thanks!