But the 7DII will not have dual Digics. Take my word for it.
It will have a single Digic 5+, same as the 5DIII and the 6D.
Here's another math that you can do:
The 1DX has two Digic 5+ processors and a 16-channel readout (official specs).
And the 5DIII has a single Digic 5+ and an 8-channel readout (again, official specs).
Therefore, it can be concluded that the Digic 5+ processor has an 8-channel readout.
Also, the 6D is capable of 20mp @4.5fps with a single Digic 5+ ... and just 4 readout channels (again, official specs).
This puts the throughput of the Digic 5+ processor at 20*4.5/4 = 22.5 MP/s per channel.
That's a throughput of 180 MP/s total for all 8 channels on the Digic 5+ processor.
Realistically, Canon will not go over 10fps in 7DII and will not put dual Digics in it.
So, I'd say that the 7DII will be spec'd anywhere between 16mp @10fs and 22mp @8fps ... with a single Digic 5+.
I'd prefer if Canon puts 16mp/10fps in the 7DII but it's more likely that they will go for 20mp/8fps.
One thing is certain, though: the dual Digic V spec is fake and this whole 7DII rumor is a lame [CR0] rumor.
Could you please provide reference that 6D has a different DIGIC 5+ processor (with 4 crippled A/D channels), than those of the 5D3 and 1D X?
All my references says it's the same DIGIC 5+ with the same 8-channel A/D, which also explains why the same DIGIC 5+ designation (e.g. not DIGIC 5-)
Assuming conservatively that 7D II is to remain at 18MP @8fps, that's ~144MPs, which is still higher than the existing 5D3's single DIGIC 5+ rating of ~134MPs. It's hard to guess how much headroom is left with a single DIGIC 5+, but I wouldn't bet on it. IMHO, it is highly probable, although not a certainty, that dual DIGIC 5+ is a real possibility for the next 7D.