Would these work?

[Snipeye]

Or even just one of them, really - look carefully at the pictures that show both screens, you can see a yellow, possibly composite, cable going into the second screen.

http://cgi.ebay.com/Polaroid-PDM-2727M- ... 35ae65dbc7

If so, pretty cheap for 7".

 

[kylerock96]

no, that is a tv out cord. besides, it is sold for parts only.