Do you have any experience with machine work? It's helpful.
Have you looked into what is required? There are a few specialized jigs and tools that will be needed.
Do you have access to a good 1911 gunsmith? What is his hourly rate? You will probably need him for something at some point in the build.
A friend of mine has built two from parts. He has extensive experience with fine machine work. He did it because he wanted to, and to see if he could. He would be the first one to tell you he didn't really save any money. I asked about the process, he sent me his copy of the book you will eventually need: http://www.amazon.com/Colt-45-automatic-shop-manual/dp/B0006EVYAU/ref=sr_1_1?s=books&ie=UTF8&qid=1367793461&sr=1-1&keywords=kuhnhausen
After reading through it, I decided I probably ought to not mess with it. You may have the skills (I don't), buy the book and see what you think.