In a 6- to 8-quart pan over high heat, bring about 4 quarts water to a boil; add shells and cook, stirring occasionally, until barely tender to bite, 8 to 10 minutes.
Meanwhile, in a 10- to 12-inch nonstick frying pan over medium-high heat, stir bacon until browned, 4 to 5 minutes. With a slotted spoon, transfer bacon to paper towels to drain.
Add enough butter to pan to equal about 3 tablespoons fat; when melted, add shallots and stir until limp, 3 to 5 minutes. Add corn, wine, and cream; boil, stirring often, for 5 minutes.
Drain shells and return to pan. Stir in corn mixture, bacon, and tarragon. Pour into a wide serving bowl.
Cutting kernels: An average ear of corn weighs from 10 to 14 ounces and yields about 1 cup of kernels. To remove them, with a large, sharp knife, cut off and discard the stem end of each ear down to the beginning of the kernels. Pull off and discard the husks and silks; rinse ears. Holding each ear upright, shear off the kernels close to the cob.