I'm also curious how the math on this shakes out, but my guess is that the theoretical curves will be the same once you equalize for aperture and format size.
I agree with Sam that there is a definite difference in how DOF and falloff appear when shooting larger sized formats. I shoot 35 FF Digital with fast primes (35 f/1.4, 85 f/1.2), MF Film, and 4x5 film so I have some experience.
I think it is rooted in a couple things.
1) For a given print size, larger formats require less enlargement. This requires less lp/mm of the lens, which means that the MTF (microcontrast) will be better, assuming equal lens quality. As a rule, the higher the lp/mm measurement the lower the MTF (contrast). This means when you enlarge less or demand less lp/mm of the lens, the contrast at the plane of focus improves. Improved contrast = increased perceived sharpness (even if resolution is equal). Increased perceived sharpness at the plane of focus contributes to the sense of DOF and subject separation, even if it is not measured by a COC calculation.
2) Larger formats typically are higher resolution (more megapixels or larger/higher resolution scans). A higher resolution file will show more fine detail when viewed at 100%. When you increase print size (which is what you are doing when viewing at 100%) then you decrease DOF. There is a point at which you cannot enlarge a print further and reduce DOF - when you run out of resolution. To me this means that a higher resolution file has the potential for shallower DOF, when printed large enough.
As an example, compare a head and shoulders portrait taken Canon 8mp digital crop with a 35mm f/1.4 L lens wide open to a 39mp MFDB shot with an 80mm f/2.8 lens wide open (or whatever the equivalent aperture is). On a 5x7 or 8x10 print the DOF may appear the same. However, on a 16x20 print the crop DSLR will be soft at the plane of focus, but the MFDB will show very fine detail on the eyelashes, with the plane of focus softening progressively as you move away from the eyes. The MFDB shot obviously has less DOF at this print size, even though the apertures were "equalized". This holds true purely on the basis of the camera's capture resolution, even if both lenses are equally sharp at their chosen apertures.
3) Tonality, highlight/shadow detail, etc. All the other image quality intangibles help things out, too.
Since photographers typically view their photos at 100% (effectively the largest possible print size), it's no wonder that all the MFDB guys insist that there is something different about MF digital.