We've tried a few different "alternative crops". Like you said, the markets are always thin and easily overwhelmed. The profits are only good if there are very few people in it. One landlord put in a Chestnut grove. He was going to leave it to the grandkids to make their fortune. This fall Chestnuts were so cheap he couldn't even sell some of them. 

We tried High Tunnel tomatoes, then every Amish within 60 miles put in high tunnels and absolutely wrecked that market, as well.