You might be coming at this backwards.
Rather than looking for a MediaWiki extension, you probably just need to do a minor edit to your template. Bugzilla has a feature that lets you fill out the submission form and then re-use those values later. But the presentation's a little weird. The button is labeled "Remember values as bookmarkable template." Once you click that, though, you're just redirected to a page that offers you a link to use, with a bunch of parameters. It'll look something like this:
(Some of those parameters are for custom fields and won't mean anything to you.)
Once you have that URL, just add it to your template wherever you want it to occur. Page-specific information should be easy enough to include via MediaWiki's own templating.
Note this feature seems to be optional. For example, Mozilla's own installation doesn't use it, but Gnome does. You might need to speak to your admin if it isn't you.