First of all, why 6.5? Most double dins fit the 7" LCDs quite nicely so I imagine a 7" tablet/slate would work just as well.
I originally looked at the Eken M001 which costs around $99, runs 1.6 but found the the screen to be unresponsive and the overall performance of the device quite slow even just for playing music.
Another device which looks promising is the Cruz Reader/Tablet costing 199 for reader which has a resistive screen and 299 for tablet which has capacitive screen. From the videos I has watched the Cruz looks to be more responsive then the Eken and has a nicer enclosure.