People may not be interested in this, and it may turn out horribly, (in fact it will probably go terribly wrong, but I'm all for that since it should be a fun sort of wrong) but I thought I'd give it a go, because it could be fun:
Sentinels Deckbuilding
Each hero builds a 40-card deck out of cards from other hero decks. There are three restrictions on this:
1) You may not use more cards than exist in one copy of the game (so no filling a deck with Eyes on the Prizes, for example).
2) You may not use cards from more than four hero decks.
3) Two player decks may not use cards from the same hero.
Themed decks are nice, but not required. And obviously references to a particular hero on hero cards get changed to whichever hero you're using, and the same with the villains.
The first rule should be fairly self-explanatory, the third is so that Impromptu Invention, Eye on the Prize, etc. don't appear in every single deck. The third is mostly to stop one player from hogging most of the heroes. Your character card should belong to one of the heroes your deck is built out of. All heroes and promos up to and including Vengeance are fair game. As for your opposition, I'm going to let the environment be neutral, and I shall be building a deck for Apostate (using no more than four villain decks).
If you're interested, claim whichever heroes you want and start building! You don't have to post a deck list; that's all on the honour system.

)