Not that I condone this, but many people have gambled and gotten rich off of doing "chest runs" in high level places such as Fissure, Tasca's Demise, and Hell's Precipice. I wouldn't suggest it, since it is a risky gamble especially as the keys are expensive. But the chance is definitely there.
One thing I
would suggest is soloing certain spots in the Fissure of Woe with a Warrior. As long as you know which enemies to avoid, and know how to keep yourself alive while doing damage, it isn't that difficult. I usually come off with 1 or 2 Obsidian Shards, 4-5k after ID'ing and selling junk to the merchant, and a total profit of around 10-12k per completed run.
Check out Racthoh's post, it does a great job telling you what to do.
Racthoh's "W/X FoW Spider Farmer" build