These were pretty tasty, but I had a very hard time getting the balls to stick together. They tended to fall apart as soon as I stopped pressing them as I tried covering them w/flour, etc. Adding more egg made it worse. More rice didn't help. I didn't want to add flour since I knew flour wouldn't cook through during the short deep frying. Adding some bread-crumbs to the mixture did the trick nicely and kept the balls together like snowballs.
I guess arborio rice or slightly overcooked rice would work better for arancini. I always de-starch my rice by cold rinsing after the first boil. It makes for fluffy rice, but for this recipe sticky rice would be best.
I used chorizo sausage in lieu of ham, chopped to bits in the mini-processor. It added a nice complexity to the flavor. Covered w/ marinara, following the Italian tradition. Green beens completed the meal.