Preheat oven to 350°. In a small bowl, combine wafer crumbs and butter. Press onto the bottom and up the sides of an ungreased 9-in. deep-dish pie plate. Bake 10 minutes. Cool on a wire rack.
In a large bowl, beat chocolate ice cream and coffee ice cream. Spoon into crust. Cover and freeze 8 hours or overnight.
For chocolate sauce, in a small saucepan, melt butter and chocolate over low heat; stir until smooth. Stir in sugar, salt and evaporated milk. Bring to a boil, stirring constantly. Remove from heat; stir in vanilla. Set aside.
Remove pie from the freezer 15 minutes before serving. In a small bowl, beat cream until it begins to thicken. Gradually add sugar; beat until soft peaks form. Serve with pie and chocolate sauce.