As a translation administrator, I want to identify previously very active translators who have been inactive for a (quite) long time to get them back to activity. Ideally, I'd also have a way to email them (semi?) automatically.

For instance it could be a command line script listing previous contributors with 100+ edits that have not contributed in the past 3 months.

This is somewhat possible by skimming Special:SupportedLanguages for big red names; it's done on Wikimedia projects by WikiStats http://stats.wikimedia.org/wikispecial/EN/TablesWikipediaMEDIAWIKI.htm#sleeping (cf. http://koti.kapsi.fi/~federico/twnstats/TablesWikipediaTRANSLATE.htm#sleeping with TWN data; maybe the reportcard will make this more portable?) and could maybe be done on twn with some other software, see https://translatewiki.net/wiki/Thread:Support/More_%28non-live%29_statistics