But of course you can (unless you are, for some reason, being extremely strict about it being an analog pedal). My Boss PS-2 has a manual shift mode, turn the knob a little bit, and your note goes slightly out of tune. Now of course, it sounds terrible, as your note is, in fact, just out of tune. But if that's the sound you want, then there it is.
Whammy pedal could also do this.
To be fair I'm only really responding to the 'detuning' issue - I haven't listened for the dubstep wobble (I think there are two distinct sounds being discussed in this thread).