Has Anyone looked at Nickel Zinc Batteries?  
reference  
http://en.wikipedia.org/wiki/Nickel-zinc_batteryavail at Amazon
http://www.amazon.com/PowerGenix-ZR-PGX1...pd_bxgy_e_img_bSame general recharge and loss rates at NiMh,  but significantly higher voltages.  Since Regular Alkaline batteries start at ~1.5, and NiMh start at ~ 1.2 voltage,  some poeple have found NiMh are not as long-lifed.  
For electronics that NEED the voltage (like camera flashes)it might be worth looking at.   Review seem to be positive. 
Disadvantages - 
requires different charger than NiMh- not compatible.  
Not good with non-LED flash lights voltage too high