I'll grant you that I haven't shot storms. I am, however, having a hard time imagining even a fast-moving storm that would have sufficient DR that you could use a shutter speed that won't move / blur in a single D800 exposure but that would be a problem with a single pair of 6FPS 5DIII exposures (with nearly twice the resultant DR of the single D800 exposure).
have a closer look at the example from a2bart from the other link.
1/1000s, f/5, ISO100.
that held the cloud hilites and motion in check. A push in post brought up the rest of the landscape and then other localized contrast and toning was used to embellish it.
That is a real-world example of a wide DR scene nicely squeezed into the DR of a print or display. An even wider DR could be accommodated using the same methods but only if the shadow noise level of the camera was low enough to not make a mess of it - as in the Fred Miranda example. You don't have to bring shadows up to midtones to see the noise from a camera like the 7D, you can leave them 3 stops below mid and there's still obvious banding.
When lively storms have clouds moving 100+ mph, trees thrashing around and all the foliage on the move, no camera's fast enough to capture 2 or more frames without serious movement artifacts to deal with in conventional multi-shot HDR. I've wasted plenty of time trying to bracket such scenes and put them together in post; results were not acceptable even in slower moving weather conditions. Not to mention re-curving a multishot HDR to try and get a
natural feeling image is a hassle. IMO, you can get a much nicer result with a simple fill-light or shadows adjustment using Adobe's products. LR4 does this with minimal artifacting or halos and it takes about 15 seconds to do it. More complex toning control is available if needed.
No more multi-shot HDR silliness for me unless I need to capture more than 9 or 10 stops of DR and present them all. Even then, I'll likely get a better result from just one ETTR raw file from one of the quieter new Nikons (or older Canons) where the hilites aren't clipped.
Um...no. Not even close. The attached HDR I did with three 5D (classic) RAW exposures manually composited. And not even the D800, I'm sure, would have had a hope of a chance at doing this with a single exposure. Notice the shadows under the fern in the lower left? That's at the bottom of Muir Woods. And notice the blue sky peeking through the top center? It's still blue.
Yes, not bad if you like that sort of look but again, multishot HDR has a hard time maintaining natural looking color and contrast. The shadow levels of that one could have been left a little lower too.
And I'd love to see what I can do with 1 shot from the D800 against a 3-shot HDR on the same scene. A nicer job in much less time, I'm thinking.

Multishot HDR has its uses, but it's not needed if the camera can handle the scene without it. And that would be any scene where the camera's noise-free DR is at least one or 2 stops greater than the scene being shot. That means the D800 and D5100 are gonna give me 2 more stops to work with, in ONE shot, than anything from Canon at this time.
You'll also notice that dynamic range was the only advantage Fred found that the Nikon had, and it had some other very crippling focus-related problems (and, frankly, laughably inferior glass) that kept him from using it for anything real.
yes, the nikon was hindered on Fred's shoot by inferior glass and a less then adequate live view mode, pity that latter especially as it's super useful on the Canons.
But to say the the better DR was the ONLY advantage the D800 had is like saying the only advantage one of these 2 motorized vehicles has is wings. Wings are pretty damn important if you intend to fly.
Glass is one thing causing me some consternation because Canon's latest TSE 17 and 24mm are on my wish list. Really wish there was something comparable for the D800 so I hope Samyang pulls a supermodel out of a cake with the 24mm F-mount version they're working on. Or maybe (chuckle) the 1DX will have a much lower noise pattern than the 5Ds...
In other words, it's the Canon, inferior DR and all, that's putting bread on his table and the Nikon that's good only for those JPEG snapshots you're referring to. And, as I've been pointing out everywhere, there's no visible resolution differences at 24" x 36".
I'd be plenty happy with the rez from my 5D2 if I could push it more. The difference in rez is secondary for this purpose. I've printed 24x36" from my 40D that looks just fine with appropriate sharpening in post, and that's at nose-to-paper distances and ~100ppi. Getting 180+ppi at the same size would only look better at much closer to normal viewing distance. I'll take it if if I got it.

No complaints about file size either. (NEF compressed raw isn't all that bad for size)