Punny Names:
* Romeo's Oat-liet: A play on "Juliet" and "oatmeal."
* Forbidden Fruit Loops: A reference to the forbidden love and the classic cereal.
* Star-Crossed Crunch: A reference to the tragic fate of the lovers.
* Love Potion Puffs: A playful nod to the potions and love in the play.
More Serious Names:
* Montague & Capulet's Cereal: A straightforward and classic name referencing the feuding families.
* Tragic Love O's: A somber name reflecting the play's tragic ending.
* Verona's Delight: A romantic name referencing the setting of the play.
Bonus:
* The Balcony Crunch: This could be a cereal with a special "balcony" shape, referencing the famous balcony scene.
For the packaging:
* You could feature images of Romeo and Juliet, or classic Shakespearean symbols like roses and swords.
* The boxes could be designed in the colors of the Montagues (blue and red) and Capulets (gold and black) to add to the theme.
Ultimately, the best name will depend on the target audience and the overall feel of the cereal.