One easy way to increase your threat generation is by the use of [item]Adamantite Sharpening Stone[/item] for sharp weapons or [item]Adamantite Weightstone[/item] for blunt weapons.
Either of these grant an extra 12 damage to weapons plus 14 to melee crit rating. In my opinion, the added damage will grant you more additional threat than using a shaman with Windfury when using a low damage main hand weapon.
At 1 x [item]Adamantite Bar[/item] and 2 x [item]Mote of Earth[/item], the Sharpening Stone can get expensive, but the Weightstone uses [item]Netherweave Cloth[/item] instead of [item]Mote of Earth[/item].
A less expensive alternative is [item]Fel Sharpening Stone[/item] made from 1 [item]Fel Iron Bar[/item] and 1 [item]Mote of Earth[/item], or the [item]Fel Weightstone[/item] which is made from [item]Netherweave Cloth[/item] instead of [item]Mote of Earth[/item].
All in all, adding weapon buffs can be an easy way to add that little extra bit of added threat, and being the awesome tank you are, you are always looking for ways to increase your threat, right