I would think that a 5D with 7D autofocus would pretty much kill off the 7D. Right now the 7D is their most high-tech supermodel of the sub-1D line.
Although a 5D/7D model would quench some complaints.
not necessarily. has the 1d ever killed off the 1ds sales because it's got the same AF? if there's anything anyone agrees on around here, it's that the 5d2 did more to kill sales of the 1ds than the 1d ever did.
FF 1ds, best AF, decent (5fps) framerate Vs 1.3x 1d, best AF, best (10fps) framerate.
Go down a rung.
FF 5d3, 2nd best (19pt) af, not as good (3.9fps) framerate Vs 1.6x 7d, 2nd best (19pt) af, 2nd best (8fps) framerate.
Sure, i'd be tempted by a 5d3, FF with ~25-30mp, 19pt AF, ~4fps.
but it'll be a lot more expensive than the 7d (or 7d2), which will have higher noise, aps-c, 8fps, etc.
even if i buy a 5d2 (or 5d3), you can guarantee i'm still taking my 7d (or 7d2) out into the field with a Great White Prime (if i could afford one) to shoot birds in good light.
same as if i had a 5d2 (or 5d3) and a 1d4 (or 1d3, 1d5). 5d2 goes to the indoor low-light and hiking for wide landscapes, 1d4 goes with the tele lens for sports.
horses for courses.