I thought Kai's DigitalRev review of the D800 seemed to implicitly state this, namely that the D800 files are so large that it is not entirely practical as a walk around camera. The Ryan Brenizer review effectively stated the same thing because he takes 250K pictures per year, which is not feasible with 70MB file sizes.
I have to say, I don't really buy this at all. I've been handling 70Mb files out of my Nikon (sorry) negative scanner for years, and I don't exactly have the latest gear, IT wise. Just a pretty regular laptop running Windows XP until a year ago, and more recently Windows 7 (32 bit). I use Lightroom 2,3 and most recently 4 on these files, with no issues whatsoever. I've digitised my entire back-catalogue of negatives, which amount to around 10,000 images. This fits just fine alongside the circa 10,000 RAWs from more recent times, onto a 1 terabyte USB drive, no issues.
250,000 snaps a year is obviously a very high total, but two points: 1. if each of these files is professional, which it must be at this volume, then clearly a professional level of storage network array is called for. 2. Not that I know beans about being professional, but doesn't 250,000 images a year sound a bit snap happy? That's over 1,000 each and every working day, and around 140 an hour, every single working hour of the day. Call me naive or old fashioned, but I'd have thought slowing down and thinking about what you are doing more carefully might be a useful strategy...