Before reading this post about a potenial FF f/2 zoom from Sigma, I had just submitted a post in this thread http://www.canonrumors.com/forum/index.php?topic=16124.15
where I said I would be keen to see a manufacturer build a FF zoom lens faster than f/2.8 - for example I said even with limited zoom range, and 24-35mm f/1.8 with great IQ.
I wrote that - as I have been very impressed with Sigma producing the APS-C 18-35 f/1.8 DC HSM- and know that something 'equivalent' for FF could be done.
However the specs of a FF 24-70mm f/2 lens would be huge (large, heavy, possibly expensive) - but I believe Sigma might be able to pull it off...! Yay
to improvements and advances.
PS edit: OS would be AWESOME.. and if HSM is spot on - even MORE kudos to Sigma. I'd love a wide to normal OS (IS) 'fast' zoom!