In my experience, any distortion pedal with both midrange and "mid freq" or "mid sweep" controls is capable of almost any tone. Something like the VisualSound Jekyll & Hyde has both overdrive and distortion circuits, plus a good EQ, and could do it. Or you should be able to get some results (albeit with less EQ control) from an old Boss HM-2, Marshall Guv'nor or Big Muff.
As an alternative, just an EQ pedal combined with your amp distortion might get you what you want. I have an Electro-Harmonix Tube EQ pedal that absolutely can nail a sludge metal tone, although that's not what I use it for.