Ekam, this isn't anything new. As time passes, advances in technology makes it easier and more economical to achieve things that weren't feasable in the past.
Gibson of CMPL had a Carputer years ago and peeps at
http://www.mp3car.com/ have been at the forefront for years.
My dream is to have a carputer one day. I'd have a wireless network, voice command, touchscreen, GPS, MP3, vid, gaming etc. It really isn't as expensive as one might think. The hardest part is finding suitable screens and peripherals (ie. mouse, keyboards, IR remotes, pwr supply). Alot of these problems have been solved now though.
And if you're interested in converting stock Navi to vid, here are the details for Acura
http://forum.toyotanation.com/showth...ght=navigation