Honestly, and I'm not joking here, I've been using slider buns for that very reason. Most full size buns are too big IMHO. I like the meat-to-bread ratio of a slider bun with a normal size (1/4lb) burger. (When I choose to have bread that is.) Guaranteed to have meat in every bite. Besides, then you can have two if you're still hungry and not feel the bread-bloat.