Thanks jrista! Everytime someone offers advice like this it helps technically as well as in the expectation department. It's easy, based on lots of 1Dx comments to assume it nails everything. Or maybe it's convenient to assume if you're trying to convince your wife you need one.
Do folks do such setups even in the wild or are you referring more to feeder type birds or maybe Serendipidy's heron
Well, can't help much in the wife department there, I'm afraid. That is each and every man's own battle.
As for the 1D X, it is an eminently capable camera, for sure. That said, slow focus is slow focus, regardless of the body used. At f/5.6 and f/8, Canon purposely slows down AF in order to support phase detection in the lesser amount of light. No way around that unless you use a cheat or a hack, such as using a Kenko TC or taping pins, but then, while AF may be fast, it is bound to be inaccurate too (or not lock at all.)
As for setups, both backyard and out in the wild, really. I may have mentioned these to you before, but you should really pick up Alan Murphy's ebooks on bird setup photography. Extremely useful tips and tricks, regardless of the setting: http://www.alanmurphyphotography.com/ebook.htm.
I've used the backyard setup photography tricks in the past to get some pretty good shots. Once I learned the trick, you begin to realize that pretty much ALL of the songbird photos you really love are without question setups. It is nearly impossible to get great composition with bird photography with 100% natural settings...there are just too many unknowns, birds are too chaotic, to really support getting ideal, clean perches and pristine backgrounds without a setup. While it IS possible to get birds in flight without a setup, for those close up action shots where birds are in amazing poses, your hit rate will be far higher with a setup than without.
I've been meaning to try setting up some raptor and owl perches, as well as groundfowl "traps" (i.e. set up a trail of seed up a makeshift ramp to a setup rock or tree stump perch for quail and pheasant) at some of the nearby nature parks. I haven't had much time lately, and the temperatures are really cold right now (teens), so I haven't had much motivation. Alan's books also cover how to use audio to attract various kinds of birds, how to bait birds, etc.