a lot of the planar and electrostat panel speakers have a very wide dispersion...also are usually on the more expensive side. You could try out Magnepan, their cheapest two way speaker is the MMG, last time i checked it was $500, but they're online only. Generally, the speakers with the wider dispersion will not go as loud as lower dispersion speakers (obviously efficiency and power handling are variables). I dont really know of any others, havent been paying a lot of attention to audio lately.