You won't really save any space by going from a 3/4 inch material to a 1/2. You would save weight, though. But if you are thinking of going thinner, why not 1/2 plywood? Working with real wood requires you to understand the fundamentals of joinery - grain direction, wood movement, expansion, contraction etc, rather than just screwing sheets together. I've made cabinets out of real wood using traditional joinery techniques, but the process is very different to the standard aracde cab build.