I think it is easy to see the attraction of the D800 for all the reasons that Jack clearly outlined ... and all at a fabulous price when comparing new-to-new pricing. I also agree that any tests should factor in the shallower DOF of MFD, and any 35 mm DSLR should be compared at the same DOF ratio, not the same f-stop. However, the OP stated that close work at deeper DOF is one objective, so in that case, each system should be tested at it's greatest ability, not to level the playing field.
Frankly, the Nikon D3X and Sony A900/850 @ 24 meg started the resolution challenge for many applications that people used the entry level MFD cameras for ... depending on the final size of use. I know this first hand because I shot at lot with both the D3X and A900 along with a H3D-II/31 and H3D-II/39. The D800 now improves on both the quality of pixels as well as the number ... but so did my move to the H4D/60 with its Dalsa sensor.
I also happen to agree with Adam, other factors come into play and are based on specific needs. some MFDs have a number of advantages over any current 35mm DSLR that some want or need, and some do not.
While I cannot speak to Phase One or the newer Leaf backs, I can outline some specifics for my continued use of Hasselblad MFD, with a continued demise of using 35mm DSLRs of any flavor as my work focus has changed and I slowly leave the wedding photography business to focus on other ventures:
∆ In at least 75% of my applications, use of studio lighting plays a key role in the work I am now doing. High speed sync, full studio flash is of paramount importance to control the ambient. All of the Hasselblad lenses are leaf shutter, and now can be used on my other MFD camera the Leica S2 ... in leaf shutter or focal plane shutter mode ... which has further eroded the need for a 35mm DSLR in my case.
∆ Like the OP, I sometimes use a full movement view camera, and in future will upgrade a few of my view lenses ... the issue of optical quality comparisons are a moot point in this regard ... there is no comparison. For less demanding T/S applications I use the Hasselblad HTS/1.5 with lenses from 28mm thru 100mm, which renders the DOF issue as a non-issue while eliminating the need for using any de-fraction f-stop. BTW, contrary to reports, using the H to S adapter the Hasselblad HT/S unit works fine on the S2 and all the software corrections also work. See demo pics below.
∆ Color accuracy with Hasselblad's True Color feature and Phocus software has made color accurate product photography a no brainer ... something I struggled with when using the Nikon D3X (it could be done, but took to much time).
∆ Malleable files have taken on more value as retouching and artistic applications have grown in importance.
∆ The True Focus APL feature has freed me to place the focus point anywhere I want with lenses like the 100/2.2 when shooting close wide open.
∆ I also use the Hasselblad waist level finder enough to mention it as an advantage.
The above are practical needs not emotionally fueled arguments for or against anything. Others have different needs and applications which drive their decisions ... not the least of which are system size and price.
-Marc
Here's a quick demo I did for a blog entry yet to be published ... the Hasselblad HTS/1.5 on a S2 using the HC100/2.2 (150mm on the HTS), The lenses were staggered and placed 14" deep. I used an optimal f/5.6 set manually on the S2 (could also have been f/8), then shot with and without horizontal tilt (the HTS rotates 360º). f/5.6 also lessened the strobe power needed and recycle was virtually instantaneous. The S2 focus confirmation worked with the HTS