Examples of some interesting Nazi German experimental aircraft are on display at the Smithsonian Udvar-Hazy Center in Chantilly, Virginia. The were seriously messing with flying-wing technology ... which was ultimately not to be made practical until the B-2.
I think Jack Northrup designed a flying wing prototype that was initially prop driven in both pusuit (at the Air & Space Museum) and bomber form. However, problems with power and control were not solved until the B-2 came along.