Motor Authority is reporting that OnStar will be introducing in car video chat for the back seat of automobiles at CES. While no carrier was mentioned hopefully the concept is a webcam and a 4G LTE modem so the back seat passengers can choose whichever video calling solution, however given that the carrier is Verizon Wireless, my money is on Skype (clearly not Google these days with VZW due to the Wallet tiff).
A big market for this will be the limousine and town car market. It will also give the reality shows a simple way to get user generated content, creating a whole new opportunity for shows in the style of HBO's "TaxiCab Confessions" to be produced without lots of production equipment. Then again, backseat lovers may have to start being more careful or they may end up on someone else's screen !