Your commander should enhance and compliment your decks strategy, without being an integral part of the strategy. I'd look at Sygg, River Guide as an example of that.
Regarding Coalition Victory, it's currently banned in EDH. It's just too easy to get a victory that way, like running Test of Endurance in an Oloro deck.
The closest thing to a crazy combination in my decks are Assemble the Legion, Cathar's Crusade, and Coat of Arms, for my Tajic token deck; and Rooftop Storm in my Grim-Grin deck, alongside Gravecrawler.