Adam you have a great problem to deal with, more business than you can handle and a waiting list. If you keep up the quality of work that you are doing you will never be wondering where your next project will come from. When people spend the kind of money they do with you they are willing to wait for the finished product because they know it is worth it. I would hold off on hiring any one as long as I could. I have seen plenty of business' that grew too big too fast and the quality of the work was sacrificed. Always know that no one is going to take care of your business and customers like you will. Keep on doing what you do and you will have them lined up waiting to get on the list.