Melt butter in the saucepan over medium heat. Using a whisk, blend in flour until smooth. Gradually add milk, whisking continuously. Whisk in salt and pepper and simmer over low heat, stirring constantly.
Cut potatoes in half and scoop out the "meat"; set aside. Chop half the potato peels and throw away the rest. When milk mixture is very hot, whisk in the potato "meat". Stir in green onions and potato peels. Whisk well, then add sour cream and bacon. Heat thoroughly. Add cheese, a little at a time until all is melted. Garnish with chives, grated cheese, and bacon crumbles.