It's not a fruitcake, but one cake I've made with fruit in it is an apple tea cake. I used
this recipe from the Taste website, substituted the sugar for xylitol 1:1, and skipped the jam glazing. Red or green apples work fine with it. It's delicious!
I saw a live performance by one of the 4 Ingredients authors last weekend, and she demonstrated her fruit cake with 3 ingredients: 1kg mixed dried fruit, soaked in orange juice overnight then add SR flour and bake. When she said it doesn't have any sugar in it I had to laugh! No added cane sugar maybe, but still a bucketload of fructose!