Probably the only solution but it isn't pretty. Can't find anything like that locally so it will be easily the cost of the chromecast just for that.

And I can't find anything about whether it will resample the audio (dealbreaker), or how it will negotiate that.

I'm sure there will be a couple of unforseen issues as well. My chromecast occasionally disconnects itself, which means that you would have to rewire the hdmi cable to the TV just to have a clue of what is going on (can my parents or house gets figure that out when I'm not around?).

And yet another device and power brick.