Line 3 (9" x 5") loaf pans with multipurpose sealing wrap (we tested with Press 'N Seal); set aside. (Use disposable loaf pans from the grocery store, if desired.)
Combine miniature semisweet chocolate morsels, toasted flaked coconut, chopped pecans, and chopped graham crackers; set aside 1/2 cup of this mix for topping.
Microwave white chocolate morsels in a large microwave-safe bowl at 70% power for 1 minute and 15 seconds. (Morsels will not look melted.) Stir morsels until melted. Microwave again at 15-second intervals, if necessary. Gently fold in combined ingredients.
Quickly spread melted white chocolate mixture evenly in prepared pans; sprinkle reserved 1/2 cup topping mixture over candy in pans, pressing gently with fingertips. Let stand 1 hour or until firm.