I second the GEC 74. Very similar, except for the thinner handle. In fact, when I first got ahold of a 74, my thought was, "wow, this is basically a thinline SBJ."
Additionally, Case makes some SBJs with thinner handles - some in bone and in carbon fiber. The Case SBJ is only a touch shorter overall than a Bullnose. And, at just a touch longer, there are some of the single blade GEC 54s popping up on the exchange. I've had a Northwoods Presidential (single spring on the 54 frame) that, although it was a straight frame as opposed to the Sodbuster's curve, was also very similar and nice in the thin profile.