here linked is a new batterie that i think would benifit sabers to a degree, mainly for the low voltage led types. It appears to be just the right voltage with a high degree of mah and excellent cycle rate.
Its a Tenergy 26650P 3.2V 3000mAh LiFePO4 Rechargeable Battery
it's roughly about 1.08 in. in diameter and about 2.5 inches long
here's the link, tell me what you think.