Brown University researchers have modified iRobots Packbot to recognise such standard hand/arm signals as "follow," "halt," "wait" and - of course - "door breach".
iRobots Warrior X700 Robot
40mm Grenade Launcher with ammo stored in barrel storage for rapid (all at once) firing. A 4 barrel version mounted on the iRobot Warrior X700 tracked "droid" has been demonstrated.
iRobot webpage for the warrior robot program.