Would remain to be seen, as it would have to be sharper than what is out there or, it would only sell to a very few.
Wanting and Working is beast's of a different color.
There is the 400 already and you can switch frames from it to a zoom.
Heck Sigma has a 100-500 2.8 fixed with a separate computer to keep it stable and it's own battery supply, whopp'n in at 28 grand, makes ya think why you don't see many if any of the large 33 pound green beasts around.
