Sandor Katz has a recipe for radish and root kimchi in his book Wild Fermentation. I haven't made it, but I have had good luck with other recipes from the book. It only calls for "a few red radishes" along with 1 - 2 daikon radishes, 1 small burdock root, 1 - 2 turnips, a few Jerusalem artichokes, 2 carrots, 1 small fresh horseradish root (or a tablespoon on prepared horseradish without preservative, 3 tablespoons or more of fresh grated ginger, 3 - 4 cloves of garlic or more, 1 - 2 onions and/or leeks/ and or scallions and or shallots or more, and 3 - 4 hot chili - all in a brine of 4 cups of water and 3 tablespoons of salt. Everything is to taste, so exact proportions of particular vegetables probably aren't really important. It doesn't sound like it uses bushels of radishes, but it might be one way to use some of them.