I would like for it to be portable.

a samsung one

You can get the regualr prtable ones that go in a little case and can strap on the back of a seat. You can also take them in other cars and on ariplanes. Or you can get the headrest ones that just slip over with a cover. That way you can switch cars with them. Panasonic or sony is the best. We have all panasonic surround sound and big screen, never any problems.