The real ones do fly The Navy & Marines use them. Since its conception, they've made great advances. I've also seen them a lot on the Discovery Wings channel. Here's the Boeing link for the Osprey.
[link=http://www.boeing.com/rotorcraft/military/v22/sitemap.html]Boeing Osprey[/link]
The home made Osprey, video I mentioned b4, doesn't look like it has tilt rotors. The other I mentioned is a "harrier". Those have been built b4. Just do a search here on RCU for VTOL.
Joe