The Matrix Audio Element S is worth a look. Very highly regarded dedicated streaming with only digital outputs.
The Eversolo DMP-A6 is also very popular. It's actually a multi function device that can be used as all in one streaming source, or just as a DAC, or just as a transport. But the price is right and the execution so good that a lot of people use it as a dedicated transport anyway.
I would look into both of those, you should be able to find them from a dealer that allows in-home trials or easy returns. Amazon might even have the Eversolo which makes it easy.