The unit has to be of good quality, doesn't have to be a recognisable name brand or look particularly flash.
Sources like alibaba in bulk quantities would also be OK. (When I search alibaba with relevant keywords, thousands of irrelevant products come up, which is why I'm asking the experts.)
The antenna is meant to be car-mounted so would probably be external. Any antenna product and technology pointers here would also be most welcome, including location of antennae, whether outside is always better than inside, etc. The following is a sample quad-function outside vehicle antenna, all I need is a tablet to go with it!
(Noob no URL rule is tripping me up, you will have to convert this!)
Hardware hacks of existing models are not so desirable -- I would rather work with a manufacturer to modify a unit with built-in jacks in the long run if necessary. A larger 10" screen model is more desirable.
e.g. there are car DVD players running Android out there with options for external AM/FM antenna and possibly others, however I need a flat screen, not looking for chunky in-dash car stereo formats.