Let me see if I understand your post. You want a system that meets all of your needs, 100%. You want all the developers of front ends to collaborate to ensure compatability. You want features that you have seen in Fords (speech recog), etc,etc.
After reviewing the state of the art as presented on this and similar boards i would have to agree with you that this would be nice to have, but is not likely to be something that you will pick up in a free, open source environment. What would be the motivation of anyone to develop and maintain such a complex system, when most potential users would just as soon pay for them in a new car with Navigation and entertainment systems now coming to market?
By adding Mac to the mix, you are further reducing the chance of a solution, as the market for Mac based apps is still very small compared to Windows.
Surely, as a software engineer you can see this