Are there any more farm spots left?

Right on Earth from patrol spawn. That building works great. On Venus where you have to get the second part for the sparrow uplink "from the story' still works. Opening the hells gate on the moon. Pick your fancy. lol

 

Here on Venus.

Enemies will spawn to the right and from the building.

Kill all enemies outside this building and run down the stairs on earth patrol.
http://youtu.be/anfkvlVaImE

On the moon.

http://youtu.be/humZOzbozmE

 

The 'Loot Stairs' works great!