Hi, we spoke about cross-wiki gadgets at Wikimania. Krinkle showed me a way to load the whole gadget+dependencies minified. It even supports automatic RTL conversion, using the user language.
// [[File:Krinkle_RTRC.js]]
(mw.loader.getState('ext.gadget.rtrc') ? mw.loader.load('ext.gadget.rtrc') : mw.loader.load('https://www.mediawiki.org/w/load.php?modules=ext.gadget.rtrc&lang=' + mw.config.get('wgUserLanguage', 'en')));
The initial check is for loading a local version of the gadget, if such a version exists. Otherwise, it'll load the gadget from mediawiki.org.
Example taken from meta:User:Krinkle/Tools/Real-Time Recent Changes.