Grace Digital Units
I have the Grace Digital Solo. For the most part I've been very happy with it. I use it mostly to stream Pandora, which it does well. I don't think TuneIn is supported, but you can check the Grace Digital site for more info if you haven't already. It can be connected to a receiver with RCA cables. Sound quality is excellent, but once in a while the audio will cut out or stutter. It doesn't happen very often, and it could be associated with a wifi signal strength issue. You might consider one of their higher end models if you don't mind spending a little extra money.
Most other devices from different manufacturers required an external display (e.g. HDTV or monitor). The Grace Digital devices were one of the very few that I found that provided what I needed and have a built in display.