and it has multiseat support, allowing multiple users to share one PC simultaneously with separate keyboards and display

I built novus, a layer on top of Ubuntu.... 5.04? 6.something? It was about 15 years ago or so, and I built software that allowed 5 users to work on a 1GB Celeron computer with 1 internal video and 4 video cards. Audio worked with 5 USB audio cards, and the mice and keyboards also all were over USB.

There was a setup program that would automatilly run of config was missing that would show a number on a monitor, you pressed the keyboard an nouse and the system knew what monitor went with what keyboard. Same for sound, a sample would play on each sound card and you'd press the keyboard for that one

We had the UI KDE with a configuration that made it look like windows XP.

It even allowed one person to run windows XP In a virtual box environment

It was meant for schools in Mexico but even though the software was near perfect, it never materialized, it was never used unfortunately