Apparently rumors are out there regarding a new Canon EOS 3D at 46mp and a "new heat dissipating design that provides industry leading ISO performance".
So, 46mp EOS 3D vs the 36mp D800. I think this works out to be about 958 more pixels in the x direction and 639 in the Y. Assuming a 36 x 24 sensor and 36 & 46 mp respectively, the (rough) pixel pitches would be 4.9 and 4.33 microns. An AA filter is probably still needed.
In the past, similar Canon announcements about "industry leading ISO performance" seems to have meant "cleaner but less sharp jpegs". It will be interesting to see what the sensor really does.
As a data point, the D3200 has a pixel pitch of about 3.8 microns. A D4X with a similar pitch would come in at between 55 - 60 mp.
Does the D3200 have an AA filter?
Would anyone switch to (or back to) Canon for this change?
As far as I am concerned, when the sensor sufficiently out resolves the glass, there is little point in adding any more pixels; and AA filters are also no longer necessary. Although having said that, Nokia claims that more pixels provide valuable statistics for noise reduction, and that by upping the pixel count above the resolution of the glass better high ISO performance can be achieved.
Assuming that computer technology will evolve to allow the handling of very large files, then:
What is the maximum effective number of pixels for an FX sensor?
In other words, where does the megapixel war end?