The main thing to remember is that the area of a DVD menu button is the whole thing. And buttons cannot overlap. So a button that goes from left to right means that no other button can occupy part of that area.
Otherwise, very straight forward.
For example, the Sunset Menu in the Encore library General set is similar. Add it to your project, then edit in Photoshop. Make the buttons wider, and add rectangles, but still a single stack. Then work with the opacity settings in the menu color sets in Encore.
Encore does funny things if you get the buttons too close to the edges, so don't push the highlights too wide.