48w bulb requires a 48w ballast. I have been reading though about people using some kind of 2x32 watt system on these. That's what I've just been looking into. Do a google search for "12 gallon nanocubes" and you will find some useful info.
JBJ does also make the 12gal Deluxe Nano Cube. It has 48watts of CF lighting and is a much better choice if you want corals. If you already have the tank and want to upgrade the hood, check out www.nanocustoms.com for some ideas.
Some people are like slinkies...they serve no real purpose yet can still bring a smile to your face when you push them down the stairs!:p
Have a great day! Brian