Slant Six mpg's?

Bear in mind that the Dart Lite and Feather Duster numbers were on the old MPG estimate systems. No accessories, and largely estimates by the manufacturer.

I am not aware of any slant 6ers who are legitimately getting 30+ mpg. If they are out there, I have not seen them advertising their successes. I especially don't see it with todays craptastic fuel with ethanol blends, etc. I have seen sporadic posts from people from time to time with the claims, but in almost all cases, it was a random highway jaunt, with no before or after testing to confirm. Bear in mind that even the length of the fuel filler tube makes a difference, as I have read that the DLite and FDuster models had a tube that did not allow full filling of the tank, presumably to carry less fuel and less weight? It would not be very hard at all to have what appears to be a killer MPG run, simply because the angle of the ground at the gas station caused the the pump to kick off early and short fill the tank by a gallon or ?
I would love to see one posting those numbers, but I get the feeling it would have to be a dynamically tuned and built combination, targetted specifically towards highway MPG, using all kinds of tips and tricks to get there. It would probably be a snail around town due to gearing, etc.