This is an old thread, but I wanted to add to this if anyone else finds it in a search. I called the IRS. They said that you can put your single member LLC's EIN on a W9. Your LLC info is tied to your name and SSN and is filed on your schedule C when you do your taxes, so they know that it's you. You don't have to use your SSN or get a separate sole proprietor EIN for W9 forms. They admitted that the instructions on the form are confusing, and had to spend a long time double checking.
