You don't need lenses for focusing to a spot, or producing spill. You simply have to match the reflector design to the emitting characteristics of the LED you're using. Take the HDS lights for example. Tight spot, great spill, one reflector, no lens.

This whole discussion has shades of "Horseless carriages will never completely replace horses". <img src="/images/graemlins/wink.gif" alt="" />