What a great idea, sounding very similar to a free project called bochs. The idea is to have a virtual machine that emulates all the hardware of an IBM-Compatible computer, and allow window to run on it and think that it is a computer.

Though the idea may have started of by looking at the bochs project, VMWare is far more complete. It emulates all hardware, and appears to do it well. I managed quite easily to run my copy of windows in a window, with very little effort.

However, this is not a real solution if you need to be able to use Windows quite a fare bit. This is because it slows down your system so much, that is is unbearble to work at. Inorder to use VMWare big time, you really need huge amounts of ram, large hard drives and multiple processors. If you can afford all this then why bother stopping at that? Why don't you just get another system minimally configured (no monitor, sound or extras (infact it could just be one of your old computers)) and run it next to your linux box networked, and use WinVNC to use it over your network. This solution will always be quicker, and is often less annoying.