I know I could get two UBB and they are tiny, but I would prefer one box with no cables (I had a Sound Pro BB go bad on me with the wire) with in and outs for two sets of mics.
The easy answer is to either DIY one yourself (battery boxes aren't very complicated), or simply glue two UGLY-BBs together. That would give you separate ins and outs (and still use two batteries, providing some redundancy) but all in one physical unit.
I have a custom 4 channel UGLY battery box with two stereo minijack inputs and one mini-xlr output. I bought it years ago from TS user Printguy.. but it was nonfunctional on arrival and I never got it working. He had Chris build it for him for use into an R44. The mini-xlr output has a break-out cable to four RA 1/4" TS plugs.
I currently use two CA-UGLY preamps at the same time. Having two physical units is less of a hassle than dealing with all the wiring. One unit with 2 inputs and 2 outputs won't streamline your wiring unless you bundle the wires together to manage them. I sometimes place both preamps into a low-cut sock which temporarily "glues them together".
Hope that helps.