Agreed, especially ones that are DSD-capable. But realize that multichannel is a sub-niche, especially when home theater (i.e video) is not part of the setup. That being said, I will soon review my third DSD-capable multichannel DAC, the new Merging Nadac. I have already reviewed (and own) the exaSound e28 and the prototype/DIY stack of three (3) Mytek stereo 192 DSD dacs. They are incredible experiences when set up correctly.
In the PCM-only world there are more, including DACs like the Metric Halo LIO-8, ULN-8, Prism Orpheus, etc.
It is a chicken-egg thing, too. While our NativeDSD.com site offers hundreds of multichannel file-based downloadable albums, there are not many other sites offering them. The other approach is SACD ISOs and extracted DSF multichannel content, but that is not mainstream in the least (read sub-sub-niche).