As a hunter I have recently been solo farming Heroic Slave Pens chests. Takes about 5 minutes now I am good at it. There are 2 chests which are easily accessible, each chest has 10gold in it and a chance for greens/blue and gems.
Here's a video of me doing it, warning fairly low quality video and I made a few mistakes on this run which I recovered from. Usually I don't get hit at all.
Solo Farming chests in Heroic Slave Pens
You can reset the instance when you are outside and i have found it will reset the chests, which is odd as i thought heroics were on 1 day timers.
I mainly do this for fun and bit of gold, the main way i make money is by cutting gems. I buy bagfuls of Adamantite Ore off of the AH for about 22g a stack and prospect it all. I then use auctioneer to scan the AH for just the gems. I can then use the auctioneer data to cut the most profitable gem for each colour as i have most of the recipes. I have made about 10-15k gold doing this over a few months.