Thanks JaideepBrar for the suggestion.
Given a vanity url example of '/annual-reports', how would you configure apache so that it knows whether it should redirect to page request in the CMS under /content/wherever or to an asset in the CMS under content/dam/wherever? And in the case of assets what request extension would you add to the request for the resolver process to act on?
Neither apache redirects nor sling mappings are author-friendly. I'm looking for a solution where, for example, an author can set a vanity URL themselves against an asset (as they can for a page), perhaps using the assets editor. We want to avoid a process that needs sysdmin/ developer involvement each time a new vanity url is added.