You will find the leatherworking vendors that sell limited supply patterns in this WoW guide. It is organized by the pattern and is in alphabetical order to make it easier to go through.

Black Dragonscale Boots Lokhtos Darkbargainer - Blackrock Depths 16 Gold Limited Supply (1) Black Dragonscale Breastplate Plugger Spazzring - Blackrock Depths 2 Gold 20 Silver Limited Supply (1) Blue Dragonscale Breastplate Blimo Gadgetspring - Azshara 2 Gold Limited Supply (1) Chimeric Gloves Blimo Gadgetspring - Azshara 1 Gold 20 Silver Limited Supply (1)

Corehound Boots
Lokhtos Darkbargainer - Blackrock Depths 15 Gold Limited Supply (1)

Devilsaur Gauntlets
Nergal - Un'Goro Crater 2 Gold 20 Silver Limited Supply (1)

Frostsaber Boots
Qia - Winterspring 1 Gold 60 Silver Limited Supply (1)

Gem-Studded Leather Belt
Rikqiz - Stranglethorn Vale 30 Silver Limited Supply (1)

Green Dragonscale Breastplate
Masat T'andr - Swamp of Sorrows 1 Gold 20 Silver Limited Supply (1)

Green Leather Armor
George Candarte - Hillsbrad Foothills 20 Silver Limited Supply (1)
Wenna Silkbeard - Wetlands 20 Silver Limited Supply (1)

Green Whelp Bracers
Jangdor Swiftstrider - Feralas 28 Silver Limited Supply (1)
Pratt McGrubben - Feralas 28 Silver Limited Supply (1)
Saenorion - Darkshore 28 Silver Limited Supply (1)

Heavy Quiver
Marda Weller - Stormwind City 20 Silver Limited Supply (1)

Heavy Scorpid Bracers Zannok Hidepiercer - Silithus 1 Gold 20 Silver Limited Supply (1) Heavy Scorpid Helm Zannok Hidepiercer - Silithus 2 Gold 50 Silver Limited Supply (1) Living Shoulders Jangdor Swiftstrider - Feralas 1 Gold 40 Silver Limited Supply (1) Pratt McGrubben - Feralas 1 Gold 40 Silver Limited Supply (1) Molten Helm Lokhtos Darkbargainer - Blackrock Depths 16 Gold Limited Supply (1)

Murloc Scale Bracers
Blixrez Goodstitch - Stranglethorn Vale 28 Silver Limited Supply (1)
Drizzlik - Stranglethorn Vale 28 Silver Limited Supply (1) Map
Helenia Olden - Dustwallow Marsh 25 Silver 20 Copper Limited Supply (1)
Qixdi Goodstitch - Stranglethorn Vale 28 Silver Limited Supply (1)

Nightscape Shoulders
Drakk Stonehand - The Hinterlands 40 Silver Limited Supply (1)
Jangdor Swiftstrider - Feralas 40 Silver Limited Supply (1)
Nioma - The Hinterlands 40 Silver Limited Supply (1)
Worb Strongstitch - Feralas 40 Silver Limited Supply (1)

Raptor Hide Belt
Androd Fadran - Arathi Highlands 25 Silver Limited Supply (1)

Runic Leather Headband
Argent Guard - Eastern Plaguelands 2 Gold 20 Silver Limited Supply (1)
Jase Farlane - Eastern Plaguelands 2 Gold 20 Silver Limited Supply (1)

Shadowskin Gloves
Rikqiz - Stranglethorn Vale 35 Silver Limited Supply (1)

Stormshroud Pants
Leonard Porter - Alterac Mountains 1 Gold 60 Silver Limited Supply (1)
Werg Thickblade - Tirisfal Glades 1 Gold 60 Silver Limited Supply (1)

Thick Murloc Hide
Blixrez Goodstitch - Stranglethorn Vale 6 Silver 50 Copper Limited Supply (1)
Christoph Jeffcoat - Hillsbrad Foothills 6 Silver 50 Copper Limited Supply (1)
Drizzlik - Stranglethorn Vale 6 Silver 50 Copper Limited Supply (1)
Micha Yance - Hillsbrad Foothills 6 Silver 50 Copper Limited Supply (1)
Qixdi Goodstitch - Stranglethorn Vale 6 Silver 50 Copper Limited Supply (1)

Turtle Scale Gloves
Jangdor Swiftstrider - Feralas 35 Silver Limited Supply (1)
Pratt McGrubben - Feralas 35 Silver Limited Supply (1)

Warebear Woolies
Meilosh - Felwood 2 Gold 27 Silver 50 Copper Unlimited

Wicked Leather Gauntlets
Leonard Porter - Alterac Mountains 1 Gold 20 Silver Limited Supply (1)
Werg Thickblade - Tirisfal Glades 1 Gold 8 Silver Limited Supply (1)

Just a reminder that all of these limited supply items listed above are patterns. If you were to search the auction house for these remember to put Pattern: in front of it. That is all I have for the leatherworking limited supply vendors. If you have more or you see an error in this list please let me know so I can update this guide.

Be sure to bookmark this page and check out the other guides for the MOST profitable limited supply items.