What's the most you would pay for a Canon EF 500mm f/5.6L IS USM?

[dhofmann]

This thread got me thinking. As Don Haines mentioned, there's a huge price gap between the 400mm f/5.6L USM and longer lenses, and surely there must be a market for something in-between. I think Canon could fit a 500m f/5.6L lens into that void. So what's the most you would be willing to pay for such a lens?

 

[Daniel Flather]

If Canon were to release any white tele lenses, it would have IS.