Here are the following quests which gain 500 reputation with their coresponding faction and 250 reputation with all of the other factions of Steamwheedle Cartel.

These will only get you as far as Neutral, from Hated, where you can use other methods which are shown in your guide.

Mending Old Wounds (Ratchet) - 40 Linen Cloth, 4 Empty Vial

Traitor to the Bloodsail (Booty Bay) - 40 Silk Cloth, 4 Red Dye

War at Sea (Gadgetzan) - 40 Mageweave, 20 Stong Flux

Making Amends (Everlook) - 40 Runecloth, 4 Coal

From infomation I have gathered, the most efficent methods will result in the following turn ins. (Assuming you choose the option where the cost of each turn in is the lowest in the quests that you will have to do do more often; ie for most realms, Linen Cloth and Silk Cloth will be the largest turn ins but it all depends on the cost factor)

1) 84 Turn ins
2) 42 Turn ins
3) 20 Turn ins
4) 11 Turn ins

I haven't been able to test this myself but it should be able to work and I know people who have done the quests as a quick alternative to grinding the reputation.

Many thanks, and I hope this is useful.

Tumak, of Deathwing EU

Just added this to the site. Thanks again, let me know if you have anything else to add...

Thanks,
Cogsworth