Polo Bikes

Anyway. I've got this volume cutter to make into a polo bike, but of course it doesn't have v-brake mounts. I'd prefer running v-brakes, so do you guys recommend clamp on jobbies or should I just get some mounts welded on?
I took my Cutter to my friendly local framebuilder, and try as we might, we couldn't find a suitable way of brazing on bosses. Seems that the back end's too narrow. Looks like a clamp-on plate is the answer.