YOu're talking about the BlueSea dual circuit plus battery switch... I installed it on my boat and two others so far.... and they're great, especially with the combiner.
That's what I'm talking about. The page referenced is a kit containing the Blue Sea Dual Circuit Plus switch, plus the ACR.
Unless somebody can come up with a down-side to this system, it's the way I'm planning to go. (Already got the ok from the Admiral and family CFO to spend the $100+ on that, as opposed to $40 or so for a vanilla OFF/1/BOTH/2 switch.) I do have one question, but I'll start a separate thread so as no to drag the OP's thread off on a tangent.