The The Secret Armory of General Knoxx Add-on for Borderlands has 10 achievements.
Completed all missions in Secret Armory
Killed Crawmerax the Invincible
Reached Level 61
Reached Level 51
Killed each of the loot midgets
Destroyed the Lance Depot
Paid for a worthless tour of the world's largest bullet
Destroyed a Lancer while in a Racer
Rescued Athena
Built the New Car: Monster