When reading about the Surly Pugsley on Sheldon Brown's site, I found the asymmetrical frame and fork ends to be a brilliant idea. I don't know if I'm allowed to post images here from the sites of others, so instead here's a link to an image on Sheldon's site for you to check out, and better understand what I'm referring to.
I'm sure there's a good reason for this, but why don't more bikes with normal-width tires use this system, at least on the rear wheel? This would allow the building of rear wheels with no dish, making them stronger. The main objection I can think of is that the drive side crank arm would not clear the chain stay unless the stay was bent in a dog leg shape right behind the rear-most arc of the crank arm. This would weaken the stay, but it could be beefed up to compensate. This Clyde for one would gladly accept the extra weight in exchange for a stronger rear wheel.
Perhaps even existing old steel frames could be asymmetrically bent to create a zero-dish setup. If there are any spacers on the non drive-side of the rear hub, you would want to remove them, then bend the non drive-side dropout in toward the frame's center-line a little, if possible. The drive side would be bent out to align a zero-dish wheel to the frame center-line . This would move the drive-side dropout ahead of it's opposite number, so horizontal dropouts would be required to allow the axle to be installed perpendicular to the frame's center-line. And the dropouts would have to be bent back into being parallel with the center line, as well.
Hmmm, perhaps it's time to experiment on that freebie xmart gas pipe MTB frame I've got out in the shop...