Did you end up finding one? Is it any good? If not, there are these: Sonicake Matribox II, Mooer GE200, Mooer GE150, BOSS Gt-1, Zoom GIX four. These all have a rotary effect. I've only tried the one in the Zoom G1X four, and it isn't very impressive, IMO. I'd like to find one with two speed controls.