JonH, a few months ago we updated our language selector. The idea you mentioned was definitely talked about yet there were a few problems that made that option less than ideal for us. Selecting a language isn't primary or secondary task for most users. Putting a language selector in the top bar though visually raises it to that level. We're wary of placing navigation and tools in the top bar area that will go largely ignored by most people. This could create some "bar blindness" now that could impede adoption of other future tools or links.
Our current implementation attempts to detect user's physical location by their IP address and redirect the user to a language if they fall into an area we've designated belonging to a translation we support. If we don't detect them falling within any of our designated translation areas, then we serve the default English (US) translation. This isn't a fool-proof implementation, but it's a solid first step. The links in the footer are the fallback options.