Toast the cinnamon-raisin bread. Tear the toast into large pieces, place them in a food processor or blender, and process to form fine crumbs.
Preheat oven to 375°F.
In a small saucepan, warm 1/4 cup of the orange juice. Sprinkle the gelatin over the warm juice and stir to dissolve. Remove from the heat.
In a 9-inch pie plate, combine the bread crumbs wht the margarine and lemon zest, patting the mixture onto the sides and bottom of the plate to form a crust. Bake until lightly browned, about 8 minutes. Set aside to cool.
In a food processor or blender, combine 1/12 bananas, the remaining 1/4 cp orange juice, the lemon juice, and sugar, and process. Add the dissolved gelatin mixture, the ricotta cheese and yourt. Puree, in batches if necessary, until smooth. Pour the mixture into the prepared crust. Chill until set, about 4 hours.
When read to serve, slice the remaining 1/2 bananas and arrange on top of the pie. Garnish with the orange zest.