As gemini6ice said in his BGG mail to you, we came up with this at a Unity Games while waiting around for our lunch party. Playing Go Fish with a different set of cards seems like a pretty intuitive idea, so I'm not surprised that multiple people came up with it. Yours clearly pre-dates ours, but I wouldn't say ours was a variant of yours. Actually, I'd say they're both just variants of Go Fish.
In any case, I think either way is a great use of the Set deck. 
