Gentlemen, the challenge: how do I make a link to where the D's start in Special:Categories?

Currently http://radioscanningtw.jidanni.org/index.php?title=Special:Categories&of... is right, but it changes day to day.

"Sure, just use [[Special:Allpages/Category:D]], and you won't even need to use {{fullurl}}" you say. However that would only work if each category page had a body. None do, so they won't be in Allpages.

Does SpecialCategories.php need to take some lessons from SpecialAllpages.php about allowing fancier arguments?