Sonos is such a tale and GigaOm has taken the time to profile the upstart, which started in 2002 and has gone on to produce a series of high-end docks, networked audio players, and an iOS controller app that ties it all together. Sadly, users of non-Apple devices have been left out in the cold and, while Sonos VP of Sales Tom Cullen wouldn't say when other versions are coming, he did at least say "We can see a handful of other potential platforms, and we want to see which one has the biggest concentration of music lovers." We say why choose one? Plenty of music lovers exist on them all.
Moving back to hardware, Cullen indicated that a person's music largely moves with them these days, and so the company is looking to moving into the
Update: Just got a note from Sonos indicating that "at no point in the near future does Sonos plan on moving into cars." So, it looks like you're stuck with any of the dozens of other alternatives for now.