Cook spaghetti according to package directions. Drain, reserving 1 cup of cooking water.
Heat a large, deep skillet over medium-high heat. Add pancetta; saute until almost crisp. Add shallots; saute until shallots are golden and pancetta is crisp, but not burned.
Add pasta to skillet; toss, cooking over medium heat. Add eggs; stir vigorously, scraping pan to loosen cooked egg. Add zucchini; toss well. Add cheese; toss. Stir in half-and-half, salt and pepper. Cook over medium heat until throughly heated, adding some reserved pasta cooking water if mixture seems too dry.