Let's say we have a directory that's searchable but doesn't have flat link architecture for Google to index all the internal/search result pages. If we wanted to add all of these static links in a way to make a link tree to guide Google's spiders would it be acceptable to make an area towards the bottom of the page saying "Click below to expand a clickable directory", and once clicked it would expand with all the links? We aren't necessarily trying to hide anything from the search engines but maintain the aesthetic of our site.
Why not just have a link to a site map which is a full tree structured "map" of all links? That would be the normal way to do it. It would have the added bonus of ensuring that all links are crawled properly and no search engine frowns on a site map.