Preheat a grill or grill pan over medium-high heat. Brush each side of the zucchini, eggplant and pepper slices with olive oil; season with salt and pepper.
Grill a few minutes per side, until slightly browned and softened. Set aside to cool.
Spread pesto over one half of the ciabatta loaf; drizzle olive oil over the other half. Over the pesto half, layer the cheese, meat and grilled vegetables.
Top with the other half of the loaf, wrap in plastic wrap as tightly as you can, then wrap in aluminum foil.
Place wrapped sandwich in the refrigerator and weigh it down with a few heavy books or something similarly heavy. Sandwich will compress considerably after 3-4 hours; you can leave overnight and serve the next day as well.
When ready to eat, unwrap, slice into 8 pieces with a sharp knife and serve.