If you can let me know the price range your looking to spend for streamer/DAC combined I can offer suggestions. By "renderer", it means that the "streamer" is built right into the DAC, rather than being in a separate box. The reason it's a better way to do things is because the "streamer" board connects direct into the DAC board using a much higher quality protocol designed for internal connections only. It can also be clocked to the same master clock for much lower jitter. Lumin and Naim are indeed examples of DAC's with built in renderers. The new Hegel HD 30 is an example of a brand new cutting edge DAC with built in renderer that just hit the market:
http://www.hegel.com/products/dac/hd30
So this ties right into why different streamers sound different. Depending on how you connect the streamer to the DAC, the quality of the implementation of the output on the streamer's vary from manufacturer to manufacturer. When the streamer is built into the DAC, it's one less variable to worry about to cause jitter and noise. It also saves on the extra cable.
The recent streamer fad we have had over the last couple years if going to start dying. This is because more and more DAC manufacturer's are starting to use the superior method of building them in.