Funny that this post showed up now, as I posted something about this in the thread below. I've already done a basic music player with library support, a few visualizations. It's designed around a 7 inch touch screen so as to have large buttons, easy selections, and simple interface. Nothing real fancy, but useable. I am also using code behind practices, so the front end can just be changed by changing the mxml, which only contains visual elements. I've got a basic one up and running now, and am looking at ham radio control. I also want to do obd-II support for sure.
But I am mainly doing it for my own purposes, and am considering just open sourcing the whole thing as I go.
Let me know how your project progresses. It will be interesting to compare notes.