Until Blizzard fixes the classic/TBC torches, here's a list of Northrend flames you can steal/honor. Grab 'em while you can for gold, blossoms to spend on food (which stacks with stuff like Fish Feasts), and goodies related to the holiday:
Alliance:
* Borean Tundra - South West of Fizzcrank Airstrip [55, 20]
* Howling Fjord - Fort Wildervar [57, 15]
* Dragonblight - Wintergarde Keep [74, 43]
* Crystalsong Forest - North of Windrunner's Outlook [77, 74]
* Grizzly Hills - Amberpine Lodge [34, 60]
* Zul'Drak - North of The Argent Stand [40, 61]
* Sholazar Basin - Southern River's Heart [47, 65]
* The Storm Peaks - West of K3 [41, 87]
Horde:
* Borean Tundra - East of Bor'gorok Outpost [51, 11]
* Howling Fjord - West of Camp Winterhoof [48, 13]
* Dragonblight - Agmar's Hammer [38, 48]
* Crystalsong Forest - South of Sunreaver's Command [79, 53]
* Grizzly Hills - Conquest Hold [19, 61]
* Zul'Drak - South of The Argent Stand [43, 71]
* Sholazar Basin - Northern River's Heart [47, 61]
* The Storm Peaks - West of K3 [40.4, 85.6]
Classic/TBC torches:
http://www.wowwiki.com/Midsummer_Fire_Festival
Semi-useful tip for Torch Juggler Achievement:
Step 1: Buy 10-20 torches from the vendor,
Step 2: Throw the stack of juggling torches on one of your keybinds. I used "1".
Step 3: Point your camera downwards and hover your mouse over your character, so the AoE crosshair is surrounding your feet.
Step 4: Spam your keybound torch + left click.
Step 5: Achievement.
Got this tip from Wowhead, and completed it after buying only 15 torches with 2 seconds to spare. If you catch the torches successfully, you don't lose them. Oh, make sure you do this in an open spot like the sewers so people don't gripe about torch tossing spam lol