backseat barbecue sounds ideal........
I can understand why you would want to enable it for kids, but if they are strapped in properly in the back they are not going to see a fat lot unless you put screens on the head rests.
The OP appears to want to watch videos himself as he/she drives along. Maybe 'safer driving' would be ideal. Or 'crash' . Either way, I'd like to see the conversation with plod/insurance company. "And why did you plough into kiddies/grannie/school crossing person?" "I was watching a film........." yup , that'll be a good excuse.
If you do get it working, post your reg up, that way , if me, my family or any other forum members get run into/over by you, we'll know why.