I have a friend who was able to do this in Manzanita OR (or its county) but not without considerable grief. You'll want to check with the cities or counties you are interested in. As this question rarely comes up, and zoning laws change, it's not something a Realtor would necessarily know off the top of their head. I do think you'd have better luck in an unincorporated (county) area than within the city limits but it doesn't hurt to ask. The department you want to start with is Planning and Zoning.
Hope that helps. Good luck! Christine