I've seen themes similar to this before but not with this particular structure. I was shooting for plenty of theme material (6 themers and the central revealer) and, oddly enough, the rest of the fill worked out pretty easily (except I'm not all that wild about MAWKISHNESS, one ugly word if ever there was one). But the key to this theme was assuring that each "double" answer had no meaningful relationship to its "single" version. My favorite is DOUBLE DIPPERS, which I think I learned from a Seinfeld episode. That's it—have fun (I hope).