help buildin a light box.

for some time now i have wanted to build a couple of light boxes for use as light when the power goes out so i dont have to keep firing up my oil lamps(yes old school but work very well except for the added heat in the summer). so here is my idea for the box and battery source, i have a couple of the RS 4x2x1 hobby boxes, 18 good 18650s(which will fit in the box just fine with room to spare). now, what i want is something with 2(or 3) levels of output, high and low(a med is acceptable) low should provide enought light to nav through a room and high should be bright enough to read with if you sit in the right spot. i am not limited to the 18650s, i could also use eneloops if you would think they would be a better option. run times are important so i have some lea way for wiring up the batteries, either 2 18650's for 7.2v or 2 at 3.7 but double the mAh, same with the AA's. so, the final piece of the puzzle, which LED and driver and at what voltage? if i have left out any needed info just let me know. im interested in seeing what ideas you all have.