It occurs to me that the easiest approximation of this would be your EBR of choice, with quad rail (or similar) furniture up front, a pistol grip attached to the side thereof so that the trigger hand and off hand are at right angles, and then turning the stock so that it is at 45 degrees with respect to each other them.
If you want a wider angle between hands, turn the forearm and the stock until you experience joy.
If you want a wider angle between hands, turn the forearm and the stock until you experience joy.