I've been listening to a lot of grindcore lately so I don't know if I can help you with the cusp stuff. :) Agoraphobic Nosbleed (left), Pig Destroyer, Full of Hell, etc. If you want more extreme I'd say Sissy Spacek (not the actress known to warble a country tune, but the noisecore trio). What I was thinking about when I mentioned above annoying a music snob was Merzbow, but I wouldn't recommend that nicely to anyone unless they had an open mind.