Good support goes along way, particularly when you are purchasing a premium product.
This is probably a dumb question but do the Titan blacks support HDMI 2.0 anyway?
No idea. I tried plugging something else into the port and nothing happened there either (our TV box) so I assume the port is dead.
Either way they can tell me when they come out

Nvidia control panel picks up the display. You can even set the HZ, resolution to 4k the lot. You just don't get any display.
I had my 1080p monitor plugged into the GTX 770 at the time so yeah, could definitely see the display and alter the settings...