Hi, Elizabeth. There are 2 sources that I can think of. One is the web. Search for log homes and check the sites for outbuildings that match the homes. Then ask for the plans, expecting to pay for detailed plans, of any that you see that come close to your desires. The second is to check the big book stores for books or magazines on log homes and go from there. I know that there are several magazines on the subject.
Don't forget that you can easily change a lot of details once you have decided on the right basic plan.