Dano is right in most cases. If you use a 3.7 V Copia LRB168B lithium Ion battery (the length of 2 @ CR123's) it should work (again, if the longer bulb focuses).
According to an email I once received from Streamlight's chief engineer, the Stinger bulb puts out about 10% more light than the Scorpion bulb. The 3.7 V 1.7 A Stinger bulb is rated to run at 6 Watts. Brock measured the Scorpion bulb at 4.8 V 1.1 A 5.3 Watts.
I think you've motivated me to experiment. The 1.4 Ah of the Copia Li-Ion vs. the 1.8 Ah of the Stinger 3 sub C battery pack is an attractive size/capacity tradeoff. The Scorpion battery(ies) are 68 mm long vs. 169 mm for 3 sub C's.