I guess it depends on what you mean by "run". You may be able to get it to boot to the initial desktop, but right away Windows 7 will disable most of the display features (aero UI) because of not enough system resources.
I wouldnt expect it to handle launching and running applications well as it will already be mostly taxed on RAM and CPU processes to just boot into the Win 7 env. I admit I am intrigued by the idea, I guess you wont know until you try. And if you do try, let us know how you make out.