Is there such a thing as a transcludable page (as opposed to a transcludable subpage)? I'm thinking of a page titled "Road naming principles" that would be quite short, basically the text I suggested earlier. It could be linked to in other articles, but it would be so short transcluding might work better.
But, that's provided it is proper convention (not to mention do-able at all) to transclude a full page.
Or an approach in which the top-level "Road naming principles" page consists entirely of its own transcluded subpage, which can also be transcluded elsewhere...?