By the way, these are past rumors, for comparison sake
I was told it would be in the $3000 price range, have a rotating zoom, weigh less, be slightly faster on the wide end at f/4 and carry the latest and greatest coatings and IS.
Ring zoom (not push/pull)
Latest IS System
82mm Filter Size
Weather Sealed
Slightly heavier than the current model
Slightly faster f/4 at 100mm (Current is f/4.5)
Retail around $2800 USD
So, that's 2 mentions of being heavier, 2 mentions of the price in the $3k range, all mention it at f/4, and the rotating zoom seems to also be likely. Then gain, this was rumored at CR2 in 2010 before they scrapped that lens, so, who knows
I'd say set your expectations at $2500 to be the lowest possible price point, and be surprised if its cheaper. Especially if they wasted R&D on a previous design