The Roland PM-3 http://www.rolandus.com/images/PM-3_L.jpg
sounds like an interesting option Clif. Are you actually using this setup on your arranger rig?
My concern is whether this system has been "optimized" specifically for drums & percussion and not for vocals (even though it says you can use it for keyboards).
Do you happen to know the weight and dimensions of the sub-woofer? The subwoofer looks heavier than my KC300 (38 lbs).I couldn't find any PM-3 specs on Roland's US web site.