Just for fun thread...
Canon make 24-70 and 70-200 f2.8 zooms. The troulbe is that to me the most useful focal lengths are 50-135mm ie the long end of one and the short end of the other. Huge financial layout asside, changing lenses all the time is a pain in the butt.
I would absolutely love a 50-135 f2.8 for full frame. I assume it'd be possible ; that's a 2.7x f2.8 zoom, similar to the 24-70 and 70-200. Canon would probably rather people jsut bought both, but I'm sure there's enough people that'd buy all 3
Maybe Sigma or somoene else who is having a hard time competing with canon on like-for-like offerings could fill some of these gaps. Oh and sigma, if you could manage f2 then I will pass you a blank check. Also, i hate extending zooms, so 70-200 style fixed size please, not 24-70 style
What other currently non-existent -- but feasable; yes we'd all like a razor sharp 10-1000mm f1.4 lens the size of a teacup, but it ain't happening -- lenses would people love to see