For filling: Seed, chop and pat dry kumquats, reserving 1/3 cup kumquat syrup. Combine eggs, 1 1/2 cups pecans, 3/4 cup sugar, 3/4 cup butter, kumquats and 3 tablespoons Cognac in processor or blender and mix well using on/off turns. Turn into bowl. Cover and freeze at least 1 hour. (Filling can be prepared ahead and frozen.)
To assemble crepes: Generously butter two 7x11-inch baking dishes. Reserve 1/3 cup filling for sauce. Fill each crepe with about 1 1/2 to 2 tablespoons filling. Roll crepes up cigar fashion. Arrange seam side down in single layer in prepared baking dishes. (Can be assembled to this point 1 day ahead, covered and refrigerated, or frozen for several days.)
Preheat oven to 350 deg. Sprinkle crepes with remaining pecans and sugar and drizzle with melted butter. Bake until bubbling hot, about 15 minutes. Meanwhile, combine 1/3 cup reserved filling, 2 tablespoons Cognac and 1/3 cup reserved kumquat syrup in small saucepan and bring to simmer over low heat. Warm remaining Cognac in small saucepan.
To serve, arrange crepes on platter and top with sauce. Ignite Cognac and pour over top, shaking platter until flame subsides. Serve immediately.