I kinda like the f-stop quantified graphs. Would be nice if LR made available a tick mark a zero offset in the histogram data so I could keep an eye on what I was actually doing in the field. Would add an absolute reference to something that is now presented as completely relative.
That would be nice, but LR with PV2012 is ill suited for that task because of its image adaptive processing with automatic highlight recovery--blown highlights may appear OK because they have been recovered. Furthermore, LR uses a BaselineExposure offset. It is +0.5 EV for the Nikon D3 and +0.35 EV for the D800. One must decrease the exposure in LR/ACR by this amount.
One can get a fair approximation of the raw histogram by using PV2010 with a linear tone curve (sliders on main tab set to zero and a linear point curve). Still, white balance has been applied, and blue or red highlights that are intact in the raw file may be clipped when WB is applied in LR/ACR. One can use UniWB (white balance multipliers all set to 1.0) to circumvent this problem.
As an example, here is a shot of a pink flower shot under florescent lighting with an approximate CCT of 2950K. The red channel is slightly short of clipping. The LR histogram using default settings with PV2012 is shown.
The raw histogram shows that the red channel is slightly more than 2 stops short of clipping. The spike in the histogram is from the WhiBal card included in the shot. The WB multipliers are 1.289 for the red and 2.176 for the blue, according to RawDigger.
To approximate the raw histogram, one can use PV2010 with a linear tone curve and apply the BaselineExposure correction of -0.35 EV. For WB, the values from an exposure with UniWB from another shot can be applied. The results are shown.
The X-axis scale of the LR histogram is not well documented, but one can get an approximate value of how far the highlights are from clipping by increasing the exposure in LR so that the highlights begin to clip and note the difference in the exposure value. The result is 1.8 EV, roughly in agreement with the RawDigger.
This is perhaps reinventing warm water, but the results may be of interest to some forum members. Likewise, I found the articles deference by the OP to be useful. They collect in one place information that may be scattered about on the internet or in the LuLa forums.