Practically any modernish short-reach rear calliper brake would work- the only variables at play these days are the axle length (longer for front) and the drop (distance to brake pads). Nonetheless, I can't imagine trying to buy one new brake calliper in the modern disk era, unless you camp out on
eBay, etc, for something specific.
It's a peculiar demand though. Single-pivot brakes have always drifted out of centre, to no cost to the rider. There's no drag from the pad that barely touches the rim. I'd ignore it till you get home. As Fossyant said, tweak it with a cone spanner occasionally.
At least a single-pivot brake will track a wheel with a broken spoke without binding, if some benefits might help.