I know this isn't practical, and I don't know if it's been mentioned here, but MenuetOS is just an amazing little 1.4MB floppy sized 32 bit OS written in Assembly with a high res (1280x1024) full colour GUI, networking and graphics capability. I've been playing with it, and as a 32 bit GUI OS [i:7350dd9b43]measured against size[/i:7350dd9b43], it's awsome.
Now if someone wanted to bring PearPC into the MenuetOS environment, that would be killer.
I realise it's impractical, I just wanted to mention it.
