Fact
Icy Veins (Oct 11), from player reports in the beta: two wandering vendors each sell one companion pet for about 60 silver with a single unit in stock. Horde: Mayhoa Skyhoof walks a route through Orgrimmar (Valley of Honor, the pond near the fishing NPCs, and between The Drag and the Valley of Wisdom) and sells the Prairie Wolf Pup Carrier. Alliance: Lil Timmy spawns at Cathedral Square in Stormwind and walks through the canals, Trade District, Old Town and Dwarven District selling the White Kitten. Respawn and restock times are unknown, no coordinates are given, and the price could change after the beta.