No, there's not.

Writing a function to do that is pretty easy though...
Code:
        private object[] combinearrays(object[] array1, object[] array2)
        {
            object[] array3 = new object[array1.Length + array2.Length];
            array1.CopyTo(array3, 0);
            array2.CopyTo(array3, array1.Length);
            return array3;
        }