Canon will be showing 500mm f4L IS II and 600mm f4L IS II prototypes at Photokina

This is not a rumor - it comes straight from Canon Japan (computer-translated) {via Foto Actualidad} - Canon will be showing prototypes of two new telephoto lenses at Photokina 2010 - the 500mm f4L IS II and the 600mm f4L IS II. The Mark I models came out in 1999. Must resist Prince jokes!

UPDATE: The english-speaking press release is now out, see it via Galbraith et al.