I can imagine this url:
http://someserver.com/wiki/api.php?wikicode=code here urlencoded&format=json&device=handheld
as a way to ask MediaWiki installed in someserver.com to render has html inside json the wikicode provided.
Do mediawiki already support something like this?
Is somewhat interesting, as make the engine "portable", so any device can render wikicode in html, even clientside javascript (with a single ajax call).