This appears to be a garbled version of a rumor published in a
European magazine a year or so ago stating that Canon was
developing two new DO lenses, a 200-400 zoom and a f/2.8 500mm.
The information came from Canon/Germany, which later withdrew the
announcement and said it was a mistake. I'm geting that info from
memory, and don't have a web page or anything to cite, but I
remember seeing a link to the original web page some time ago. I
don't know that anyone outside the inner echelons of Canon knows
whether these two lenses are actually under serious development, or
whether they are some marketing person's pipe dream.
I agree that the 2.8/500mm would be a dream lens, but there's no
way I could afford it! My impression is that the 400/DO hasn't
really taken off, mainly because of the steep price. After that,
Canon may decide not to develop more lenses using the tech. Only
time will tell.....
Mike B. in OK