Unlock these bonus missions be acquiring the requisite number of awards:
Tunnel - 10 awards
Ruins - 25 awards
Plaza - 40 awards
Airport - 60 awards
Covert Suit - Found on the Station T level, you can find it on top of the big safe in the room with the final bomb.
Dinner Jacket - In Q's Headquarters in the second area of the garden maze.
Dinner Suit - Open the drawer in Moneypenny's office in level 2.
Snow Suit - You'll be able to get it in the Factory mission.