MCM Electronics has a lot of accessories for the Raspberry Pi credit-card sized computer, including little composite video LCD monitors. Some have exposed circuit boards, so you will have to devise some sort of case. Others are more finished - like a small monitor. You will also need to check the required voltage. The coin appearing in most of the photos is a US quarter dollar - about 15mm diameter.
First up (1.5 inch diagonal):
http://www.mcmelectronics.com/product/83-14397
[img=left]https://dashcamtalk.com/forum/data/MetaMirrorCache/www.mcmelectronics.com_content_productimages_s2_83_14397.jpg[/img]
Next (2 inch):
http://www.mcmelectronics.com/product/83-14398
[img=left]https://dashcamtalk.com/forum/data/MetaMirrorCache/www.mcmelectronics.com_content_productimages_s2_83_14398.jpg[/img]
Next (2.5 inch):
http://www.mcmelectronics.com/product/83-14399
[img=left]https://dashcamtalk.com/forum/data/MetaMirrorCache/www.mcmelectronics.com_content_productimages_s2_83_14399.jpg[/img]
Next (a bit bigger at 3.5 inches):
http://www.mcmelectronics.com/product/83-14400
[img=left]https://dashcamtalk.com/forum/data/MetaMirrorCache/www.mcmelectronics.com_content_productimages_s2_83_14400.jpg[/img]
More (4.3 inches, no exposed circuitry, maybe the best choice):
http://www.mcmelectronics.com/product/83-14401
[img=left]https://dashcamtalk.com/forum/data/MetaMirrorCache/www.mcmelectronics.com_content_productimages_s2_83_14401.jpg[/img]
Finally (the biggest at 7 inches, and no exposed circuitry. I got this one for testing my ITB-100HD, but not for a permanent connection. It works nicely.):
http://www.mcmelectronics.com/product/83-14402
[img=left]https://dashcamtalk.com/forum/data/MetaMirrorCache/www.mcmelectronics.com_content_productimages_s2_83_14402.jpg[/img]