I'd point out at the possible expense of being obvious that if you shoot test shots for moire, you'll eventually get some, because you'll be shooting the kinds of patterns that provoke it. My feeling is the resolution on the plain-vanilla D800 will be so good that if you shoot a lot of fabrics (which I would think is where you'll see most moire, because of the fine and repetitive spacing of the elements) then maybe you should just go with the 800. The Nikon comparison shots of the kimono with the plain D800 you can clearly see individual threads and stitches in the fabric, and I don't know that anyone who shoots a lot of fabrics would need any more resolution than that. I mean, what would it be for? Moire could pop up in other places (shots of TV screens, possibly in small tile patterns shot at a distance so the patterns replicate the tiny tight patterns of fabric) but I think those situations would be rare indeed.
Then, there's the working process to be considered. I suspect people who shoot a lot of fabrics could be the kind of person who might make a hundred shots in a day, and plan to use all of them -- sample shots, for example. And it would be a pain in the ass to remove the moire from a hundred shots on a daily basis. For landscapers, however, don't usually use all 100 shots in a day, and moire-producing patterns are much rarer. A landscaper may shoot a hundred shots, but may choose only one or two (or maybe none that day) to actually print. So, he's dealing with a much smaller project in removing moire -- he finds it less commonly, and processes fewer pictures.
I used an M8 for several years, with very good glass, with all kinds of general subjects, and occasionally saw moire...but really, not all that often, not so much that it bothered me. But really, with resolution as good at the D800, I see really little purpose for a general shooter like myself to go with the 800e.