Scramble eggs to your preference and dice thick slices of ham. Set aside.
Stir the hard-boiled egg yolks into the rice. Line a bowl with plastic wrap, and spoon some of the rice into the bowl. Spoon scrambled eggs and diced ham into the middle of the rice. Use another spoonful of rice to cover the scrambled eggs and ham. Use the plastic wrap to form the rice into a ball. Set aside while you work on the details.
Hole-punch two eyes out of the nori. Cut a triangle for the nose, and two strips for the eyebrows. Cut two circles out of the cheddar cheese for the ears. Stick the nori and cheese onto the yellow bear rice ball.