I finally found the rails!! He is using what appears to be rails from a Compellent CT-SC030 server or similar model that can be found at: https://www.serverworlds.com/compellent-s114-r16-p11-series-30-40-controller-rail-kit-ct-sc030-ct-sc040/
If you just type in Compellent CT-SC030 or CT-SC030 on eBay, you can usually find the rails on the beginning side if you sort by price. Hope this helps everyone!
P.S. I just ordered a pair of these and will update on receiving!
Currently, there are no optical Thunderbolt 3 cables on the market that span that length. I have contacted Corning (the ones with the optical Thunderbolt 2 cables Linus used), Thunderbolt, and Intel. Corning can't comment on anything they might be working on, Thunderbolt has no idea, and Intel won't respond. These optical cables were supposed to be out in late 2016 according to Intel. So for now you are limited to using a Thunderbolt 2 card with a Thunderbolt 2 optical cable and a Thunderbolt 2 dock.
To answer your question regarding your displays, the Thunderbolt hub you buy really determines what displays you can run. On the Thunderbolt 2 hubs that I have seen, you are limited to running DisplayPort through the Thunderbolt 2 port via an adapter and having an additional HDMI port. There are specs at the bottom of the Elgato Thunderbolt 2 Dock website (this is the dock Linus used). Link: https://www.elgato.com/en/dock/thunderbolt-2
From my understanding, this would meet your needs because the HDMI spec is as follows: "HDMI output up to 4096 x 2160 pixels at 24 Hz, 3840 x 2160 pixels at 30 Hz, and 2560 x 1600 pixels at 60 Hz" and you can add your 144hz display over a Thunderbolt 2 adapter, given the adapter supports that refresh rate.
That seems to be your best bet unless you want to wait for Thunderbolt 3 optical cables. The Thunderbolt 3 hubs have a DisplayPort instead of an HDMI port and a lot more bandwidth for daisy chaining. Link: https://www.elgato.com/en/dock/thunderbolt-3
We want to make this happen. It's still unclear how it'll work especially with respect to music licensing.
It's possible we will have to eliminate the "download MP4" feature and force people to stream outright.. but if we can find a way to keep it, PLEX integration is something I personally really want to see.