Not exactly a module per se, but I can see immediately how this could also fit into a smaller modular rig, especially one being used along with some Volcas. Three channels (one is stereo) with 3.5mms, AUX send/return, compressor, channel mutes, DC supply onboard for three other Volcas, stereo out plus onboard speakers. It's sort of a simpler take on KOMA's Field Kit without some of the more esoteric functions. But unlike the Field Kit, this device has a master clock for Volcas and, presumably, other devices that can sync to Korg's sync standard.
Apparently it just dropped this weekend at Winter NAMM. Those looking for a small-rig mixer, especially something portable, might want a peek at this thing. http://www.korg.com/us/products/dj/volca_mix/