@Pedro I've been thinking. While your idea of pillaging a screen from a dead laptop would be a great idea, the problem becomes fitting a case for it. Unless you want to spend more money trying to make the case for the screen, what about getting a laptop, thin or not, and simply leave the screen inside the laptop bezel and do one of two things:
1. take everything out of the base and place the control board in there instead(including the keyboard, unless you have a board that can convert the keyboard to a usb plug). use the extra space to put speakers, batteries, a storage for a keyboard, whatever.
2. the other option is to still take everything out, but instead, chop/slim the base down enough to fit the control board, and some speakers. add a support on the back of the screen. Then cut some material to cover the now gaping hole and glue it/mount it together.