Trying to ask a better question this time. I want to define some extra markup in the search-block-form.tpl.php file, and I know how to do it in a theme. But, how do I do it in a module? I'm looking for my module to use the .tpl file from my module instead of the one provided by the search module, but still generate the same search form. Make sense? It's probably something to do with the hook_theme() call, but I'm struggling to find the right magic.