Built a nice little PiKVM and deployed it in my NAS. The NAS is heavy and placed in a dark half-height place under the stairs so it’s awkward when things go wrong and you need hardware access.
Not aware of any such project. I’d assume you’ll need some hardware anyways as you need it for the level of access (ATX etc.). Not sure how that would be preferable to this.
I was thinking more about the basics, like USB input and getting the image+sound. For that you could get away with a special USB cable and a capture card. I'm just not aware of any software for it, I don't think the original PiKVM stuff was ever ported to PC.