Question: With the ability to migrate questions, I have found quite a few duplicates on both SU and MSO due to questions being migrated from others sites.

Do we handle these as normal duplicates or should we just let them be?

Answer: 
This was implemented with the Mortarboard (bronze), Epic (silver), and Legendary (gold) badges!
I don't think the Mortarboard, Epic, Legendary badges are quite the same.

Those badges simply award (repeatedly) hitting the rep cap; this question is asking for a badge for going beyond the rep cap

I'm no Jon Skeet, bu on many days, I've received thirty or forty votes for answers given after hitting the cap.

I think that there should be bronze, silver, and gold badges for getting 10, 20, and 40 votes on answers *given* after hitting the cap.