The first Wild Pitch mix I heard was of a Sven Vath track, of all things. DJ Pierre kept busy in the early 90s!
I've never really heard the style described with any precision. Anyone want to take a crack? I've also heard the term 'Wild Pitch' for the beatmatching technique where you throw a record on, cue it and let it go once, and then do everything else with the pitch slider. I don't think that has anything to do with DJ Pierre.