I'm planning a few experiments to see if I can find a hardware solution to dithering graphics cards. So far I have two things to try.
Firstly I'd going to chain several powered signal converters together and see if the loss of clarity is sufficient to prevent any dithering induced discomfort. What I mean is something like this: hdmi to vga converter -> vga to hdmi-> hdmi to vga. I'm expecting the resulting picture to be somewhat blurry but perhaps usable.
Secondly, I have just discovered devices like this:
What this device does is accept a 4k hdmi signal, and outputs a 1080p signal. This is an interesting idea, as its for every four pixels of input, it will output a single pixel, thus any dithering across the original 4 pixels should be lost.
There will be downsides to both methods if they work, though a hardware solution would be great for work where I may have only limited control of the software and internal hardware of whatever pc I am given. I will keep you all informed of my progress.