In a large bowl, beat the softened cream cheese and powdered sugar with an electric mixer until smooth. In a separate bowl, whip the cold heavy cream and vanilla until stiff peaks form. Gently fold the whipped cream into the cream cheese mixture, then fold in 1 cup of Fruity Pebbles. Cover and refrigerate for at least 1 hour.

Preheat oven to 375°F (190°C). Brush both sides of each tortilla with melted butter and sprinkle with cinnamon sugar. Bake directly on the oven rack for 5-7 minutes until lightly golden. Immediately drape the warm tortillas over the rungs of an oven rack or an inverted muffin tin to form a taco shape. Let cool completely until crisp.

Melt the white chocolate wafers. Place 1.5 cups of Fruity Pebbles in a shallow dish. Dip the top edges of each cooled taco shell into the white chocolate, then immediately dip into the cereal to coat. Let them set completely on a piece of parchment paper.

Transfer the chilled filling to a piping bag with a large star tip. Pipe the filling into each decorated shell. Garnish with a few more Fruity Pebbles and serve immediately.