I've been advised to bring up the following proposal, which takes the needs of smaller wikis into consideration, here (actual discussion has taken place at http://en.wikipedia.org/wiki/Wikipedia:Village_pump_(proposals)#Highlighting_possible_internal_links_in_the_editor):
This proposal refers to internal links to already created pages. Entering text into an editor, we can create an internal link by adding double square brackets around a phrase which agrees with the title of a wiki page. Couldn't such agreements be pointed out to us automatically? A background color, for instance, could highlight phrases like "internal links" after having typed them into the editor with the double square brackets being set when double-clicking on the highlighted phrase. Every possible internal link could be represented that way and we would just have to double-click those which we want on the page. Another background color could be used for possible links to disambiguation pages, which would give us the opportunity to adjust the possible links so that they would link to specific pages rather than disambiguation pages. Of course, internal links would still have to be created the old way if we wanted phrases to link to pages with which they do not agree, i.e. if piped links are required.