For what it is worth, I just had two of these installed:
Two 7" monitors each with their own DVD players (so you can watch something different on eiter side)
In replacement ebony leather headrests
with two sets of wireless headphones
with power converter and Xbox power pigtail located under the seat. Just plug in the box to power and your rca cord and you are ready to go
$1800.00 installed.
(They are in my wife's new Denali Envoy)