For full range, multiple drivers configured to approximate a point or short line source might image almost as well as a single driver can because the geometry of how the sound propagates is similar.
There are some omni designs that do this trick with inherently wider dispersion in 3-d. Morrisons, Wolcotts, and OHM Walshes are good examples.
Small monitors and some floorstanding Totems like the Arros are other examples in a more conventional box design.
I like these designs for good imaging best, especially for more nearfield listening. For listening from a distance in some larger rooms, taller line source or floorstander designs with multiple drivers can work better as well.
