Best Buy has new Insignia roku 4k tv's for cheap so I thought I would give it a try. The have a 43",50", & 55" for $399, $499, & $649. I figured i'd give it a shot and see if I could get one to work as a monitor for me. Compared to the price of a Wasabi Mango, and the ability to easily pick it up and return it to a store in the US this sounded like great idea to me.
I was able to get a 50" Insignia tv working with 444 chroma @ 60hz. It has a native resolution of 4096x2160. Color depth is 8 bpc.
On a side note my 280x doesn't have an hdmi 2.0 port so I had to get a 1.2 mini DP to HDMI 2.0 adapter.
I bought a 43". I have a Gigabyte GV-N670WF2-2GD. It apparently does DP 1.2. Is this the only adapter you could find that did HDMI 2.0 and 4:4:4? I was considering upgrading my graphics card but if the adapter works I may just use that. I have it running at full reso but at 30hz. I am also running a 27" 1080p monitor under my glass table as a lower monitor. My viewing depth the screen is over 3 feet on this glass table. So far I can run, an ONKYO HDMI stereo to a 42" plasma at 1080p, the Insignia 4k at 30hz and the 27" at 1080p 60hz. I need another HDMI port for audio pass through to a TV in the bedroom which is a 720p. I realize I am crushing the ability of the graphics card and was considering adding another NVIDIA. I have just the DP 1.2 port open at the moment. On another note Windows 10 has a hell of a time remembering where things were depending on which screens are open.
This was the only adapter that I found that did hdmi 2.0 at 4:4:4. I'd love to see a picture of your setup, that sounds insane!