How many more hot dogs can a vendor outside the Metropolitan Museum of Art sell at the north side of the museum entrance, as opposed to the south side? First-time vendor Pasang Sherpa is betting he can unload at least $81,701 more lips and assholes, because he's coughing up that much extra for the north location, even though the southern spot is only 100 yards away. Sherpa paid $362,201 to the Parks Department for rights to vend at the north side and $280,500 for the south, but now he's fuming because the more heavily-trafficked north entrance has been blocked by construction won't be done until May. "I don't want to pay them now," he tells a Post reporter, who theorizes that this might be the most expensive retail space per square foot in all the land.