Looks nice and I absolutely support such ideas, but 9600 mAh still seems doubtful. From the picture, it looks like you're either using 4x ~14500 Li-Ion (model, not capacity), or even NiMH's (I hope not, for your device's sake).

Even taking into account possibility of 4x 14500, they would hardly get 9600 capacity in real life. Even 8000 mAh would be very good result. It is just what they've sticked on label, or you've actually did on-device measurement?

Generally, more technical details, please. Cells, who produce them, where bought, what you've used to mount with N900...

/Estel