LONDON (Reuters) – Designer Christopher Bailey sent his models down the runway in an explosion of rainbow-colored metallic trench coats as part of his latest spring/summer collection for Burberry. Models strode the catwalk in corsets, pencil skirts and sleek silk dresses in raspberry pinks, emerald greens and sapphire blues, laced with a metallic edge. Trench coats, a Burberry staple which reaches back to the company's foundation, appeared in a variety of different forms. …