I found this quite by accident (and it's no April Fool's Day joke): On Zap2It's list of "Other animated characters 'Playboy' should consider," in the vein of Marge Simpson, a list which contains such females as Wilma Flintstone, Aeon Flux, Penelope Pitstop, and Jem And The Holograms (!!!), we have this entry:
#12: Hawkgirl -- Wonder Woman is way too obvious.
Nevermind that Wonder Woman, or at least a girl painted up like Wonder Woman, made the cover of Playboy. But Hawkgirl? Seems incongruent to me. Like she would bonk bonk any photog on the head. Go figure.