Alright, so this is a dumb format idea I just had:
1) Players build 24 card decks. They may have up to one copy of any card other than basic lands. 2) At the beginning of the game, each player exiles the top four cards of their library face-down. Once everyone is satisfied with their hands, turn the exiled cards face-up. 3) Whenever a player would draw a card from an empty library, they do not lose the game. Instead, they lose one life for each player with an empty library. 4) Laboratory Maniac and Jace, Wielder of Mysteries are banned.
Play otherwise proceeds as normal.
That second rule is to discourage fragile combo decks - there's roughly a 17% chance that any given card will be exiled at the start, so you might want to build around that.
I think the ban list could do with more cards. Probably.