People on this Nintendo forum thread have come across this alleged Zelda screenshot on the Revolution. It originates from Hyrule.net, who have had this to say about it:
This screenshot popped up out of nowhere, seems to have no source and above all, looks fake. Sorry guys, there is no Zelda Revolution material yet.
The screenshot certainly made me go ´wow´ - but it´s almost futile to discuss this one seriously without knowing where it came from. I´ll mail Hyrule.net. You go ahead ;)
EDIT It´s confirmed fake. Thanks to Neodozzprime for opinting this out to me and Hyrule.net for finding the original. It´s 3D art by some artist called Dragos Jieanu. The piece is called Bridge to Avalon.