You might be better looking at building your own battery pack.
One of these
http://www.gearbest.com/diy-parts-and-tools/pp_119294.html four decent 18650 batteries and a decent stand alone charger is all you need
@fossyant is the resident expert
Pannovo/Solar storm Battery boxes are really good. The new ones do USB and have a power indicator, BUT, the power indicator does discharge the batteries, so if storing then remove the top cap. As for batteries, anything with 'fire' in the name should be avoided. Torchy the battery boy on
ebay is one to go to for batteries. You need a UK seller for lipo batteries, due to air freight restrictions.
If you just want a two battery holder, C&BSeen sell them, and batteries if you want. It costs a little more to make your own packs, but they are far more reliable. If you also invest in a smart charger, you can pop the batteries out and charge them in that to ensure all cells are 'balanced'.
With the cheap packs, you'll find one battery dies, leaving the pack useless. If you have a smart charger, you can pull the packs to bits and test the cells in the charger. Any good cells can be used in Cree torches.
Good battery makes are Pannasonic, sanyo, efest, senybor and Xtar. Xtar are a big manufacturer of smart chargers.
The pannovo packs can be charged with the standard magicshine charger, but I'd recommend a smart charger that you can recharge the batteries individually - you do this every once in a while. Ideally get 'protected' cells.
With a protected cell it stops over discharge and charge. If the cell is 'tripped' it won't charge in a smart charger. What you do is pop the batteries back in the battery box, and connect the magicshine charger - this resets the protection chip.
I have Senybor 2800mah batteries (protected) and Panasonic 3400mah (unprotected) and a load of 2400 mah no name ones from dead packs which I use in my Cree torches
