The iPad 3/4 screen is a fantastic option for a MiSTer setup, with a native resolution of 2048x1536.
As mentioned in a previous post, information on the screen model, driver board, and housing is available here. However, finding a quality power supply can be a challenge, if you decide to piece your own kit together. There are a few options recommended by those in the scene. In particular, I can vouch for this one:
Tri-Mag Specs: Voltage - Output 12V / Current - Output (Max) 2A / Power (Watts) 24 W
You'll then need to pair this with a barrel jack adapter measuring 5.5x2.1 to 3.5x1.35 - you can find these on Amazon. Now you can enjoy responsive, high resolution gaming on a modern 4:3 screen!