Researching the vertical mount GPU myself, found this video:
Could be your video of the completed mod (same case etc), not sure, but either way it's cool and may give others inspiration. The rubber grommet was a neat touch.
For my case, I'm looking for a similar style aluminium (is the correct spelling lol) bracket but for 5-7 slots so I can mount 2 GPUs and a sound card, perhaps a SATA 6Gb/s card (old motherboard) in the area of my horizontal slots. Might just remove the metal between each of the slots and create a mount at the top and a support at the bottom. It's not a fancy case so just has to work but is early days yet...