For a wider neck, get a couple of 1x2s from Home Depot, and one stick of 1/4 inch by 1.5 inches. Glue stand them on their sides and laminate them together with wood glue, the 1/4 stick in the middle. Cut to shape.
howdy slowfoot,i have a link to the history of the tennesse music box,i will post it here for you if i can.i decided to try out building a few of them keeping as much as i can to the original appointments but adding a few modern appointments. they are basicly squarebox dulcimers with different applications for tuning keys and frets and things like that. http://home.usit.net/~sandyc/mb.html here is a nice informative link that will answer a lot of your questions.