I haven't tried the regular Stinger, but I suspect the Ultra-Stinger may have a longer throw...recently I acquired the "Easter Seal Headlite III" -- (
http://www.caves.org/imo/frames1.htm -- go to "headlamps" and scroll down..)and replaced the original bulb with a (edit- Xenon Star 4 cell, 5.2 volt, .7 amp 3.6 watt ) Carley lamp (pr-flanged type, I'm using it with the five aa NiMH battery pack..) -- the spot is extremely tight - too tight for most situations I'm sure many would say -- but this makes the throw amazing! Most of the time I can use the Headlite3 on the first one or two of it's four brightness ranges, (four being brightest) and haven't had a heating prob yet...not bad for $50...
plus the light has a regulating circuit to keep the bulb at a constant brightness over the life of the batteries..and when the battery wears down, the Headlite3 goes into a pulsing mode, to let you know you have only a few minutes left to change batts..
re: the Plasma Beam group buy -- how much would that be again..? (They're $3200 I see on the net,,)
(edit-) I tried a side by side comparison of the Headlite III with the Ultra-Stinger last night, and they both had very similar throws, and sized hotspots, the U.S. was about twice as bright as the Headlite3 though...