Nice video. I always wanted to grab a GUS for some of my old PC games.
I'm pretty happy with my MT-32 though.
On topic though, I did some experiments on my main PC in pure DOS 6.22
I have an AMD R9 290x, and have it hooked up to my plasma via HDMI and my ASUS VQ248QE via Dual Link DVI-D.
No analog signal whatsoever.
I made a USB MSDOS 6.22 boot, and used a spare 80GB drive to create a 2GB FAT partition, and installed some games on it. KQ5, QFG2, and Daggerfall.
All of them ran PERFECTLY (no sound though, because dos drivers for modern hardware will never happen), and even weirder, the signal to both my TV and Monitor was 1080p60hz.
My R9 290x was automatically scaling everything up regardless, complete with rectangular pixels.
I kind of want to buy an old DVI-D PCI or AGP video card and pop it in my older computers and see what it outputs now.