Badge suggestion: A badge for for having ten migrated, worthy but slighty out of scope, highly viewed or upvoted questions. Maybe call it the "Golden Goose" badge? Are there any badges for combined Stack site questions?
No. There's no badge for that because a migrated question generally indicates that you posted it in the wrong place initially. Badges are supposed to reward positive actions, not bad-but-not-that-bad.
All badges currently only take your actions on one site into account. The idea of cross-site badges has been floated around now and then on the main meta.