Page transclusion with variable substitution

Requested by customer through a support request.

One very best things about MediaWiki that Confluence lacks (I think) is the ability to include one page inside of another (transclusion) while simultaneously doing variable/token substitution at page render time.

To see how popular this feature is, just click on the Random Article link on the left side of Wikipedia over and over and you'll see that the vast majority of pages you come across have just such a template-based box on the right side, with various data filled in. This same approach is used for the notes at the top of many pages about how the page should be improved. (See http://en.wikipedia.org/wiki/Help:A_quick_guide_to_templates for the details.)

Is there any way to achieve the same thing in Confluence? The "Include Page" macro does let me include one wiki page inside another, but it apparently doesn't have any ability to substitute values into the rendered page. And Confluence's built-in template support is not useful here, because the template is not referenced again after initial page creation.