Rod and Tod! That'd be a classic choice, as I remember that episode where they show R&T in the future, and they're both on the front lawn, either washing a car or painting some furniture, and they're both dressed in Freddy Mercury shorty-shorts with obvious insinuation!
Good episode. In it, an older and now blind Ned thanks Bart for "not outing Rod and Tod". Now that's pretty clear. Whether or not there's the an incestuous taboo violated as well, we can only guess. Perchance they married to avoid death taxes? The scoundrels! After all, tax avoidance would be the gravest law violated in a land such as Springfield.