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