I would be nice if this were in an "affordable" range, but I'm not holding my breath.
At the same time I'm wondering about the f5.6 maximum aperture with a 1.4 TC. Which means this would only autofocus on the 5DIII and 1DX with the extender, correct? Could this be an indication that the 7DII will autofocus at f8? That would certainly be one way to add value to the next generation.
I don't see Canon releasing anything with an 'f/8' maximum aperture.
5D3, 5D2, G5X, G16 | SY14/2.8, V20/3.5, 28/2.8 IS, Ʃ35/1.4, 50/1.8, 50/1.8 STM, Ʃ50/1.4 EX, 100/2.8L IS Macro, 16-35/4L IS, 24-105/4L IS, 70-200/2.8L IS II, 1.4x II, 2.0x III, T28-300 VC PZD, 70-300L IS, Ʃ150-600 OS HSM S