Well a favourite of my stealthers was the first chest in Underbog, it was very easy to open with 2 people, without having to kill any mobs.
If you having trouble remembering where it was, it was next to the water, in between the water and tree just as you came around the corner from the entrance.
Unfortunately this chest was removed, as the week before it was removed i had found a way to solo farm it.
So for old times sake i'll post the strat.
For rogues, you have to be an engineer, or have something that can be thrown at least 35 yards. (decapitator maybe?)
For druids, it's a lot easier if you have nature's reach, or of course you can also have some kind of engineering or other item.
Stealth all the way past the first boss, and circle above where the chest used to be.
If you stand on the edge, you could moonfire, or rocket launcher one of the mobs guarding the chest.
Let them run all the way up to you, and when they almost reach you, drop down, and run into the water (avoid the fishies) Being in the water for a short period of time will drop you out of combat, then you could go loot the chest.
Of course sometimes the chest could be locked, and your still limited to 5 instances per hour.
Unfortunately this was nerfed in the same week i found it, so i didn't get to run it very often, and now never again :(