Anyone who actually shoots 35mm, medium, and large format knows that really, no foolin', no myth, even without tilts and shifts, it's easier to do short DOF with a larger format and ordinary lenses.

Running some numbers through f/calc (available from http://fcalc.net), which is a handy program for calculations like these with all the formulas included in the help screens, I get a DOF range of slightly less then a three inches using a 300mm lens at f:8 on an 8x10" camera (acceptable CoC=0.188022mm) with a subject distance of six feet. I get a DOF range of slightly more than a three inches using a 50mm lens at f:1.0 on a 35mm camera (acceptable CoC=0.02501mm) at the same subject distance, which would be typical for a portrait. So if we call that even, you need an exotic f:1.0 wide open lens on a 35mm camera to do what you can do with a typical modern plasmat made some time since the 1970s (300mm/5.6) on an 8x10" camera stopped down one stop. Tessars in that range would usually be 300mm/4.5, and a 12" Dagor is f:6.8.