For crust: In a medium bowl, stir together all ingredients. Press into bottom and up sides of a 10-inch springform pan; refrigerate.
For filling: In a small bowl, stir together lime juice and gelatin; let stand for 5 minutes or until softened. In a small saucepan, cook ½ cup cream and white chocolate over low heat, stirring frequently, until mixture is melted and smooth. Stir in gelatin mixture until dissolved, and let cool completely.
In a large bowl, beat cream cheese, sugar, and lime zest with a mixer at medium speed until combined. Add white chocolate mixture, and beat at low speed until combined.
In another large bowl, beat remaining 2 cups cream with a mixer at high speed until soft peaks form. Fold whipped cream into white chocolate mixture, and pour into prepared crust. Cover and freeze for 8 hours.
Remove from freezer, and gently run a knife around edges of pan to release crust from sides of pan. Garnish with white chocolate curls and lime wedges, if desired. To serve, cut into wedges using a knife that has been dipped into hot water and dried between cuts.