Is it possible to convert a Canon lens to a Sony body?
No: the Canon EOS system lens mount has a shorter registration distance(*) than any other 35mm SLR mount (Sony/Minolta alpha, Nikon F, Pentax K ...) so attempting to mount Canon lenses on bodies from those other systems puts them too far from the focal plane, making the lens short-sighted (losing infinity focus).
On the other hand, Canon EOS mount is the universal recipient of other 35mm format SLR lenses, while Nikon and Pentax lenses are the ones most easily adapted to use on other mounts. Also, most Nikon and Pentax lenses have aperture rings, which helps when using on other bodies!
Now, if Sony launches a non-interchangeable lens system akin the Micro Foru Thirds, it would presumably have a greatly reduced registration distance, allowing all kinds of lenses to be adapted to it ... with the main exception being Canon EOS lenses, due to their reliance on electronic control of aperture and everything else. Canon EOS lenses are the only major SLR lens type that cannot be used on m4/3 bodies with adaptors.
(*) Distance from lens mount to focal plane.
