A lot of launch vehicles have a lot of mix-and-match options as far as upper stages, fairings, boosters and so on. This was certainly true for the Atlas. Shown below are some of the building blocks possible, from a Convair presentation of April 1967.
Scott, you’ve tried this, right ?
http://kerbalspaceprogram.com/
Think of it as orbiter with more explosions.
Okay, what is the Hammerhead?
“Hammerhead” is term were aerodynamic cover has a bigger diameter as it launch rocket
like Titan 4 http://upload.wikimedia.org/wikipedia/commons/5/56/Titan_4B_with_Cassini-Huygens_on_board_with_the_second_launch_attempt_at_Lauch_Pad_40.jpg