Preheat broiler. Place marshmallows on a small baking sheet and broil until golden on top, about 4 minutes.
Pour melted chocolate on a small plate and crushed graham crackers on another.
Dip glasses into chocolate sauce to rim mugs, then dip in crushed graham crackers. Scoop ice cream into each glass, then pour chocolate milk on top and add a splash or more of Baileys Irish Cream.
Add whip cream.
Top each float with two marshmallows, then drizzle with your choice of syrup, sprinkle with more crushed graham crackers, and add all other toppings desired.