Do you have any performance benchmark information? For example, how many channels does one encoding server support? What are the actual resolutions and hardware specs for this?

For an AVC-based Apple HLS and MPEG-DASH set as it is present in the MainConcept Live Encoder we can do 8 channels on an Intel Xeon E5-2699v4. This is basically using the most balanced presets with regards to quality and speed. If you can live with slightly lower quality, more channels are possible. This covers 1080p, 720p, SD, mobile in different flavors. Please keep in mind that the results can be influenced by the codec, resolution, bitrate, hardware, etc.