leonardmc: Thanks for the reply, I think that almost anything digitally available via lds.org or any official site would be OK, although there may be a few with IP permissions issues that could not be used.
I'm thinking everything from 2001 on for General Conference, CES firesides, other meetings of general interest, most but not all of the segments in the Sunday School DVDs, some other material, and Mormon Messages, etc. That would provide a substantial 'starter' collection'.
Now for audio matters such as Mormon Channel. We're moving more and more towards intermediary devices being used to bring web content to the home and car, for audio there's a lot of chatter about Internet radio in the car, some manufacturers already have production-ready devices already being sold. And here's a blog post about one such way this is happening.
It's obvious that some variations of the Mormon Channel app would have to be made for displays like this, most smartphone displays are vertical, while the sample display shown is horizontal.