Tim sells a 4 pole 5-way switch. I think with 2 of these in a guitar you could really get any combination. I have one in an HSS guitar to give me 5 h/b sounds (bridge, bridge screw + middle, bridge+middle & neck as hb,bridge slug+neck, middle&neck as hb). With a second 3 way I could add parallel or tap.
Just a thought, why do you want coil tap when the volume works with bare knuckles :P