I listen to a lot of experimental/avant-guarde metal, but based on the ones you listed I don't know how much you would like some of my recommendations. I'lll list them anyways, as I may be wrong:
Ved Buense Ende - Meloncholy black metal that incorporates a lot of dissonant and twisted riffs.
Peccatum - One of Ishahn's now disbanded projects. I know there are some people here who would argue that this band is shit, but they were pretty brilliant if you ask me.
Sleepytime Gorilla Museum - Not completely metal but when they are, it's pretty crazy. They blend elements of dark folk, Rock In Opposition (RIO), prog rock, No Wave (in a song or two), amoung other things. I don't know if you'll like them though. They are really deep in the whole avant-garde stuff.
Unexpect - These guys are all over the place drawing influences from classical, jazz (at times), carnival music, even gipsy music. Pretty out there, yet still somewhat accessable.