[Crazy Jetty]

Then and Now sets would be pretty cool.
Package Twpacks or Multipacks with versions of their first appearances, with their most recent costumes.
Or maybe Gallery sets, that follow the progression of a character's most notable costumes. Like Rogue in her original outfit, her gothier black suit and green top, her Jim Lee costume, her X-Treme Costume, and her modern costume.
These wouldn't do well in retail stores, but I think they would do well as e-retailer exclusives. Sell them through online resources only. Great way to fill up gaps in collector's shelves, that children may not care about.
Be a great way to one-up Matty Collector, by allowing more retailers than just HasbroToyShop to sell them.