It should be possible since the GPU is a mini card and the socket supports faster CPU's. Is it cost effective is the main question, those parts are usually high priced and not readily available in retail!
I'm sure you're right about the cost. Do you know of a place where they would sell parts of this nature?
I'm not overly concerned about the cost (well, to a point anyway). I'm a tech and will pretty much doing it for the experience and the fun.