Don't be too hesitant in thinking because the 1DX is FF it won't cut it as a serious wildlife camera, the IQ is good enough to allow ample cropping especialy when mated with the 800L.
Coupled with a TC and yes, AF tends to slow a tad and you'll be restricted to the four centre focus points.
Or, you can lift your bushcraft stalking skills and ditch the TCs.
Got an invite a couple of months ago to try out 1DX, replied for january but heard nothing since
Guess nothing is going to come of it, am currently looking to upgrade my 1DM3, and will probably have to opt for 5DM3
Canon should not have abandoned the ASPH crop pro body, they are a bunch of *******
And where's the 7D replacement, not to worry, they have gone all full frame and cine
Disappointed I haven't had a crack at the 1DX as promised , but as i use an 800mm with tcs a full frame isn't best suited for my needs