If you don't want to use bacon, you can easily use 4 chicken sausages instead; just slice into rounds, saute in pan, then stir into pasta like you would the bacon.
If you want to make this vegetarian, I think a can of rinsed and drained white beans or even roasted, crunchy chickpeas would be a really nice option.
Feel free to use a different pasta, such as orecchiette or angel hair pasta. I prefer orzo because it keeps the pasta nice and creamy. Feel free to add in more veggies.