I don't think it would be as good as Fallout 3 cause Fallout 3 took... 4 years to make? While New Vegas is being shorten by a year (I don't know how long it's been in the works). Sounds like a cool game though, maybe you'll be able to see what happends to Vegas' landmarks. x]
They bought the rights in 2004, worked on it, and it was released in 2008.
They did? Wow, where have I been? But where would Oblivion factor in? They released it after much delay in 2006 I believe.
2006-2008. Two years I'd imagine. Those are now Bethesdas' main series's. Also Fallout 3 had a very similar if not identical physics engine to Oblivion as I recall.