Line a loaf pan with cling wrap, leaving edges out. Soften gelato until easily scoopable and fill loaf pan in a checkerboard pattern, varying each flavor and scattering coffee beans throughout. Tightly pack loaf pan, fold cling wrap over top, and return to freezer to harden. When ready to serve, remove from freezer and from loaf pan. Place terrine on cutting board, and completely remove cling wrap. Using a warm sharp knife, thickly slice the terrine. Mix the chocolate sauce with the espresso, and drizzle over the plate. Place two slices of terrine on each plate and serve immediately.