Am I correct to assume that it is then a just another
page? If so, the
interwiki takes precedence over a local page.
Perhaps we can make the : character an invalid character for page titles.
There are plenty of legitimate uses for a colon in a page title.
Perhaps local pages which start with something which is also an
interwiki prefix should take precedence over the non-local page. Some
way to link to the non-local page would be required, of course.