i can't think of any solos that sounded slowed by any artist. i'm not disputing that it's done.. i just can't think of anything off the top of my head. example, please?
i also can't think of a time that i've ever liked the sound of what i've played slowed down, other than when i'm trying to isolate a particular segment and can't think fast enough.
but i'm not by any means a professional, so i'm sure it's application is beyond my technically-limited vision at this point.