I basically did the same thing with the front, cutting the pieces, gluing them, then filling in any parts that were missing, only this time, I filled then in with plastic. Soon I will make screw holes, and then attack the two halves together, get the back the exact same shape as the front, then make them have a proper lip to fit together, then put in the electronics, then take it apart, sand, and paint!
Here are some pictures, keep in mind that I have just been applying the plastic, I haven't started to really shape the outside yet.