With the 3.1 patch, fishing dailies are being introduced.
One reward from the Fishing Daily is a lockbox (called Tiny Titanium Lockbox) which requires 405 lockpicking to open.
Which means that Blacksmiths cannot open (400 skill for Titanium Keys) or Engineers (360 skill on Seaforium) which means you have only one way to open them, and this is where money is to be made....
A rogue with maximum lockpicking with a pair of Dark Leather Gloves.
Now this gives the chance for money for 2 types of people:
A Rogue.
A Leatherworker.
Rogue:
Max you lockpicking as soon as you can (Violet Hold is very good for those last couple of points, but you can only do it once per trip to Dalaran).
Buy/Make a pair of Dark Leather Gloves. Prices of these will soar when 3.1 hits.
Pickpocket mobs for the required Lucky Charms in 3.1.
Leatherworkers:
Buy recipe (if you don't know it already). It's a world drop with a rate of 1.3% (according to WoWHead)
Stock up on Dark Leather Gloves and start selling them.
The current materials are:
Fine Leather Gloves (Cured Light Hide, 4 x Light Leather, 2 x Coarse Thread)
Cured Medium Hide
Fine Thread
Gray Dye
In patch 3.1 the mats will change to:
8 x Medium Leather
2 x Lucky Charm (Pickpocketed from these mobs)
Fine Thread
Gray Dye
My wife is a Leatherworker (I'm a Rogue) and she's currrently selling these for 40G a pair. At the moment she's selling about 2-3 pairs a day, but obviously demand will increase when 3.1 hits and rogues learn they need a pair to open the lockboxes (whilst I'm making money from opening and pickpockets mobs for Lucky Charms)