Has anyone attempted to recreate the Sack AS-6 (German Saucer-wing)?
I'm not aware of anyone making a replica of the Sack AS-6 (the aircraft was destroyed when the Allies reached the area); however, there are other examples of saucer (circular wing)- like the Rowe UFO, which flies quite happily.



Rowe UFO; image from youtube grab

Then there is also the Vought V-173, whose design is quite similar.



Vought V-173 By Unknown - http://www.flickr.com/photos/sdasmarchives/4822056685/, Public Domain, Link