This can be done with custom HTML and CSS. Although I can't personally advise you on that, I have seen various tutorials online, and other Community members may be able to help you as well.
I must agree. I would like to see a plugin/app that will apply breadcrumbs to pages that I wish to add them to. I do not wish to extend any further custom coding to the client's site. The reason the client went with Weebly was to get away from extensive customizations.
