Basically this is a list of the shiny hunter gear available from the different factions and how to get the rep needed for it. They're listed in order of rep needed from least to greatest. I skipped the Horde factions, but a quick glance tells me there's a nice bow and a dagger. I also ignored all the patterns since this is a gear list. I have only listed mail armor, but there is some nice leather stuff out there as well.
1. Cloak of Holy Extermination-+39 Agility, +57 Stamina, +52 Attack Power, + 25 Armor Penetration
2. Zombie-Sweeper Shotgun-+14 hit rating, +18 critical strike rating, +68 Attack power, 117.6 dps
3. Polished Regimental Hauberk- +89 Agility, +69 Stamina, +68 Intellect, yellow socket (socket bonus +4 to hit), +49 hit, +104 Attack Power
Gain rep by dailies and quests in Zuldrak and Icecrown, as well as wearing their tabard in dungeons.
The Kalu'ak (they also have a pet and a really nice fishing pole available at exalted)
1. Cuttlefish Scale Breastplate-+56 Agility, +84 Stamina, +32 Intellect, +82 Attack power
2. Traditional Flensing Knife- +29 Agility, +28 Stamina, +58 Attack Power, +21 Armor Penetration
3. Whale-Stick Harpoon- +69 Agility, +103 Stamina, +40 hit, +100 Attack Power
Gain rep by quests and dailies in Borean Tundra, Dragonblight, and Howling Fjord. This is a nice faction to get leveling gear from.
Kirin Tor (besides the gear, all the vendors in Dalaran are Kirin Tor faction, so grinding rep with them will give you a nice discount)
1. Lightblade Rivener+29 Agility, +30 Haste, +58 Attack Power
2. Spaulders of Grounded Lightning +34 Agility, +51 Stamina, +34 Intellect, +34 critical Strike, + 34 resilience, +68 attack power
3. Boots of Twinkling Stars"+42 Agility, +49 Stamina, +41 Intellect, +58 Haste, +66 Attack power
There are quests in Borean Tundra and the Colderra, and the cooking and jewelcrafting dailies also give some rep. Other than that, it's wearing the tabard in dungeons.
Knights of the Ebon Blade
1. Unholy Persuader-+30 Agility, +46 Stamina, +29 Armor Penetration (this is probably more of a rogue weapon)
2. Runeblade of Demonstrable Power-+63 Agility, +67 critical strike rating, +33 haste rating, +168 attack power, 169.3 dps
3. Spaulders of the Black Arrow- +58 Agility, +42 Stamina, + 44 intellect, +33 critical strike, + 88 attack power
There are quests in Icecrown, and once you've unlocked the quartermaster, wear the tabard in dungeons.
The Sons of Hodir (these are the shoulder enchant guys, and I didn't list those, but it's a good reason to grind rep with them. They also have mammoth mounts.)
1. Giant Ring Belt- +40 Agility, +51 Stamina, +34 Intellect, +25 Critical Strike, + 102 Attack Power
2. Broken Stalactite +26 Agility, +28 hit, +33 critical strike, +48 attack power, 130 dps
There are quests and dailies in the Storm Peaks. No tabard for this one, sadly.
The Wyrmrest Accord (they have a red drake as well)
1. Fang of Truth-+32 agility, +29 stamina, +33 hit rating, +48 attack power
There are quests in Coldarra , Icecrown, and Dragonblight. There's also one daily in each of those zones.
1. Toothslice Helm+34 agility, +80 stamina, +52 intellect, +34 critical strike, +138 attack power
2. the Mysterious Egg (has a chance of a drake mount or vanity pets
this faction has no hunter gear, but does have a potion thing similar to the egg.
Both factions can be found in Sholazar Basin, and there is a long quest chain before you can start either set of dailies. Be aware that if you switch allegiances after buying gear you will no longer be able to wear the gear till you regain the rep.
Alliance Only Factions
Alliance Vanguard (subfactions are Explorer's League, the Frostborn, the Silver Covenant, and the Valiance Expedition. You need to be exalted with two of them or have the equivalent rep spread out over more than 2 to be exalted with them. Not wearing a tabard in dungeons gains you rep with them.)
1. Sawed-Off Hand Cannon- +17 Agility, +27 stamina, +18 to hit, 95.8 dps
2. Vanguard's Soldier's Dagger-+27 Agility, +36 Stamina, +40 Attack Power, 106.0 dps