Now that I've made a fair bit of coin off of this, I figured I'd share. When you hit 325 JC, you learn the recipe for a Purified Jaggal Pearl. At this point, raid the AH for any regular Jaggal Pearls (they usually go for 25s-50s a pop on my server) that have a buyout of roughly 85s or less. Obviously, the cheaper the better. Now, just grind away creating and vendoring the Purified Jaggal Pearls for a gold a pop. However much less than 85s you paid for each Jaggal Pearl is free gold. The reason for the 85s cutoff is that the Purified Draenic Water needed for the recipe costs about 15s per pop (a little less, actually).
What you end up with is a formula roughly like this:
(1 gold vendor Purified Jaggal Pearl) - (15 silver Purified Draenic Water) - (Whatever the cost of the Jaggal Pearl was) = Profit
And yes, this doesn't seem like much until you consider how quickly it can scale (depending of course upon your server's economy), especially with the right addons (such as ones that buy off the AH automatically under a certain price, open mail in bulk, vendor specific items in bulk, etc). Even if you only made an average of 50 silver off of each, if there were two hundred of them on the AH, that's a quick hundred gold for pretty much zero effort.
A few preemptive strikes:
1) Yes, I know on your server Jaggal Pearls might be more precious than an hour undisturbed with Natalie Portman and have buyouts of hundreds of gold. This clearly will not work on your server. Bummer.
2) Yes, I know there are faster ways to grind gold, but I know of none which can grind gold this fast with this little effort shy of botting. Mass buyouts, "Create All", mass vendor. Done. This is a tip aimed at the lazy, not the greedy.
3) Yes, I know this might be considered "common sense" to some, but if it truly was, I wouldn't still be able to make a couple hundred gold a day doing this.
4) Yes, I know this isn't a "guide" in the truest sense, and simply more of a tip, but this is the forum in which it seems to fall best.