I can't give you three, but I can give you one great one.
Mark Shepard's New Forest Farm is here in Wisconsin. Here is a blurb about it from the web:
"Mark is the founder and President of the Restoration Agriculture Development, and CEO of Forest Agriculture Enterprises. He teaches Agroforestry and
Permaculture worldwide and has also written the book, Restoration Agriculture. He runs New Forest Farm, the 106-acre
perennial agricultural savannah, considered by many to be one of the most ambitious
sustainable agriculture projects in the United States.
Mark and his wife Jen founded New Forest Farm in 1994. It’s now one of the most developed and productive perennial farms in North America –
trees, shrubs, vines, canes, perennial plants and fungi are planted in association to produce food (for humans and animals), fuel, medicines, and beauty.
The farm is a planned conversion from a typical row-crops grain farm into a commercial-scale, perennial agricultural ecosystem using oak savannah, successional brushland of eastern woodlands as the ecological models. The farm is entirely solar- and wind-powered, and farm equipment is driven by locally produced biofuels."