WotLK Beta - Tabard and Faction Reputation.

There are 5 Major Reputation Factions in WotLK best I can tell though 6 of them offer faction gear. Those being:

Knights of the Ebon Blade.
Argent Crusade - They have the Helm Enchant at Revered Arcanum of the Stalwart Protector.
The Wyrmrest Accord.
Kirin Tor.
The Sons of Hodir - They have the Shoulder Enchant at Revered Lesser Inscription of the Pinnacle. At Exalted Greater Inscription of the Pinnacle.
The Kalu'ak - Faction gear but, No Tabard.

Each of these factions all have Tabards you can pickup at their respected QM at "Friendly" with the faction. The exception is with "The Sons of Hodir" who currently as yet does not have a Tabard or a QM in game as yet or not yet implemented. But the other 4 have a Tabard that you can earn reputation with other than through quests and dailies of each.

You can pick up "ALL" the Tabards if you like at Friendly and just wear whichever one you want in any lvl 80 Dungeon and you will earn reputation points on behalf of that faction in that lvl 80 Dungeon. You get a Buff when the Tabard is worn to indicate the faction behalf your gaining reps with and doesn't do anything else otherwise.

Trash: 5 point.
Mini Boss: 10 points.
Boss: 30 Points.

So which ever lvl 80 Dungeon or Raid you like to run just wear that Tabard for that Faction and you earn rep points for your reps on that Faction behalf and counts for your Faction reps. Those points add up abit also and I've being wearing the Argent Crusade Tabard for Reps and they do add up in lvl 80 Dungeon runs. Does not work on low level instance only instance considered lvl 80 Dungeons.

Each faction has items fairly easily obtainable at by doing most the area quests or dailies and reaching Honored that's very usable especially for Tanks. So when you can or in zone for any these factions check out the QM and grab you a Tabard.