I've been using Quasi TV (android app) to try out the concept. I remember having something similar back in the boxee / xbmc days. I especially liked that it "just worked" without having to set anything up besides pointing it at my plex. I'm not afraid of hosting something, but I didn't want to go through the trouble if it turned out I wasn't going to use it.
I quite like it. Unfortunately, the app's been a bit buggy - not always picking up the stream at the "current time" and sometimes navigation gets wonky. But it was a good test run and that, along with your post, has convinced me to give Ersatz (or something like it) a try.