If you are looking for the absolute longest "throw" as we call it and don't care about overall lumens as much, the a small emitters like the Cree XP-C, XP-E, XR-C, or XR-E; or the Luxeon Rebel (non-ES) would be the ones to choose from.
I listed in your other thread where to get Rebels. My favorite source for Cree emitters is Cutter.com.au since you can buy more exact bins as I prefer neutral ones, but Digikey also carries Cree LEDs.