privatebydesign said:
I'd be very surprised if they came out with two versions of the high MP sensor with and without an AA filter.
Agreed. I don't have the rumor/leak details the CR Admins have, but I wonder if there's some overlap between 'one camera with AA filter and one without' and 'a high-megapixel 5Ds and a lower megapixel 5DIV'. If I were to guess, it would be that the 5Ds lacks the AA filter, and the 5DIV retains it (i.e. just two bodies, not three). That wouldn't seem like throwing things against the wall to see what sticks. An "S" body has been missing from the lineup for quite a while, and a successor to the 5DIII is expected. Seems reasonable to me...
I might be wrong, but isn't the need for an AA filter reduced as the pixel density goes up? That might support Canon's decision to remove it for the 53MP body.
Now, to tread into areas I have even less knowledge...When it comes to resolving power of lenses, I don't see how 53MP would be an issue. We don't run into resolving power issues on the current crop sensors (or do we, and I just don't know?), so having similar pixel density on a full frame camera should be fine, right? It also wouldn't be a compromise on noise performance because full frame's advantage is a function of more surface area to gather light, not pixel density (because of gapless microlenses). Anyone with expertise on the subject, feel free to set me straight (Neuro, jrista, Lee Jay -- I'm looking to you guys

).
Anyhoo, this is what I'd sepculate:
1. 5Ds High-Megapixel for $4,999
2. 5DIV for $3,499
3. 6DII for $1,999
The high-megapixel body will be released long before the 5DIV. This would be to entice 5DIII users (particularly studio and landscape users) to make the jump from their aging 5DIII workhorses, and at early-adopter prices. Once that pent-up demand is satisfied, they release the 5DIV as a true upgrade/replacement of the 5DIII to feed the wedding/portrait/event market the 5DIII has served so well. The 6DII will have a few incremental advancements that keep it in the "entry level" category but are nice enough to justify the boost back up to $1,999. I wouldn't be surprised if the 6DII doesn't come for another year or more, though. The 5DIII second hand market might also push 6DII prices back down to $1,799 pretty fast, too.
It would be cool if Canon did something that blows everyone's minds at launch. For example, leap-frogging 4K and debuting a higher resolution standard with clean output and a powerful codec that keeps file sizes reasonable. Of course, the Cinema EOS line pretty much guarantees that won't happen in a DSLR. Or maybe Canon introduces a new sensor architecture that mops the floor with any current products for dynamic range and ISO performance.
Realistically, I think the acknowledged focus on serving the high-megapixel crowd and the high-sensitivity crowd separately is a pretty good indicator that a mind-blowing, do-all sensor is not coming any time soon.
Oh well -- I'm just excited for another generation of full frame bodies to be released so I can decide if I get the 6DII or pick up a current (then previous) generation body for much lower price. Either way, it's good for me.