Pour 1 inch of water into a pot large enough to contain all the lobsters. Bring the water to a full boil. Remove the bands from the lobsters' claws and place them on their backs over the boiling water. Cover the pot tightly, and steam over high heat about 3 minutes. Quickly remove the lobsters from the pot and chill them rapidly by plunging them into a basin filled with ice and water. Set a wire strainer over a mixing bowl. Twist the tails off the lobsters over the strainer to catch their juices. Shell the lobster tails and claws over the strainer. Cut the tails into 4 quarters, leave the claw and knuckle meats whole, and reserve the lobster meat in a refrigerator.
Peel the potatoes, split each into 4 wedges, and slice the wedges into 1/2-inch slices. In a large non-reacting soup pot, cook the diced bacon over moderate heat until golden and nearly crisp. Pour off all but about a generous tablespoon of the fat. Add the diced leeks, stir, and cook about 2 minutes. Add the potatoes, stir, cover the pot, and continue cooking over moderate heat, stirring frequently to prevent browning, until potatoes are tender, about 10 minutes depending upon the potato variety and the thickness of the slices. (Chef's Note: I like to mash some of the potatoes with a fork to give the chowder a luxurious but rustic texture, but good mealy potatoes, such as russets, will release some of their substance into the broth, and this step may be unnecessary.) Add the strained lobster juices and enough water, lobster or fish stock, to just cover the vegetables. Simmer 4 or 5 minutes. Keep the chowder base hot as you prepare the lobster meat and cream enrichment.
Heat the butter in a wide skillet. Add the lobster meat, season with black pepper, and saute over moderate heat 3 or 4 minutes until the meat is firm, opaque, and pink. Pour in the heavy cream, and rapidly bring it to a simmer. Pour the lobster and cream mixture into the chowder base, and stir gently to combine. Taste for seasonings, and adjust with sea salt (preferably from Maine), plenty of fresh-milled black pepper, and a pinch of chipotle or cayenne pepper. Off heat, cover the pot and allow the chowder to ripen for 15 or 20 minutes before serving. Ladle into warmed soup plates, and sprinkle snipped chives over each serving. Accompany with plenty of warmed common crackers.
Serving Suggestion: Crackers .
* Chef's Note: Don't attempt to use half-and-half--it tends to curdle.