Since Sanctuary is basically the new New Haven, I was wondering if there were any secret chests in the city that are farmable as they were in New Haven for Borderlands 1. I know there is supposed to be an NPC that hands out free loot but I don't know where he is at (I guess that technically isn't a chest >.>). I tried to hop around and didn't really find any, but I could have easily missed them.
The answer is, there are none.
At least as far as I know, and I did search very very closely. I went to every corner, inspected every wall, jumped on top of the highest roofs, did my best to look at every angle and did not spot any chests at all. You only find those small boxes with money inside, and one of those usual "vault" secret sign which I think gave me a badass point.
There is a hidden chest in Dr. Zed's place. I got a purple sniper rifle and a blue assault rifle from it. It's on top of the overhang behind the sign reading ZED.
It's not a normal loot chest. It's just one of the cardboard boxes. There is a chance to find guns inside, though. I just found a pistol.
Hard as hell to get up there.
If you look up at the sign at the front of Zed's you should be able to see a cardboard box with the green label. Note that you don't actually need to get up there to open it either. You can just jump up as close as possible to the sign and open it in mid air. Usually takes a few jumps though. Only found ammo myself so far.