It would be nice to see (perhaps it already exists) an ethernet card for a PC that also looked, in hardware, like all the other standard PC hardware. In particular like a basic standard SVGA video card, like a soundblaster, like a keyboard and like a mouse.
But in fact, all writes to these devices would be sent out over the ethernet. Writes to the video memory, sounds send to the sound card and so on.
This would be very handy with the server crowd, no need for consoles, kvm switches or having to physically go to a server to do work on it. There are tools to provide virtual services after machines have booted (and of course unix/linux machines have always been completely remote controllable after boot, and even during boot via serial console.) And indeed, with this card you would throw in smarter virtual drivers for devices after the operating system had booted that made more efficient use of the ethernet, or supported different resolutions.
Include jumpers to read all motherboard LEDs while at it. If you wanted to get really cute, put a tiny microphone on the card fed into the sound-card portion, so you can listen to noises the drives make etc.
The card could of course do wake-on-lan to the motherboard and have the ability to power off the machine as well. A physical visit to a machine would never be needed except to physically change hardware.
Eventually this would all go onto a standard I/O chip and, like all these peripherals are today, come standard with the ethernet that's on every server motherboard already. Virtual USB systems already exist if you want that, and might be a simpler solution for keyboard, mouse and sound in any event since new motherboards and their BIOSes are now used to seing those things on USB.