There are not many opportunities left for making money selling low level grafted gear. Blizzard added even more heirloom items in Cataclysm - cloaks and helms that you can buy if your guild is of enough high level. That said there are still several gear slots which you have to fill with dungeon drops, quest rewards or... crafted items. The neck slot is one of such.
Here are several necklaces that I make and successfully sell:
1. Malachite Pendant. I told about it in details in my post Today's Special: Malachite Pendant.
2. Thick Bronze Necklace. Another neck piece that is good for any low level character because +3 stamina is a nice boost for any class. The materials are:
It costs about 2-3g to make and can be usually sold for 15-25g.
3. Necklace of the Deep has two red gem slots. This makes it so powerful that it can not only make leveling a rogue or a hunter through Outland very easy but also last well into Northrend or even till the Cataclysm gear can be equipped. Though many players prefer leveling through dungeons and can get their amulets there, I can still sell 2-3 of these each week. The materials are:
It costs about 50g to make and can be sold for 150g.
These are the items I am consistently making and selling. I will look more into low level jewelcrafting and update this post if necessary.
The next post will be about tailoring, and the list of items there is a little longer.
Have a nice day!