Our MoP Classic item table (the Blizzard item records our Auction House scanner has collected) has 9 other mail chest items between item level 245 and 289; 5 of them carry fixed stats.
Cheapest listed mail chest items at a similar or higher item level: Sundown Vest at 19 gold (item level 283, requires level 79), Bramblescar Vest at 32 gold (item level 289, requires level 80), Nazferiti Vest at 95 gold (item level 272, requires level 77).
Other armor types for the chest slot within 6 item levels of 264: leather (1): Ikfirus' Sack of Wonder.
Connected realms with a listing in the latest MoP Classic scan: EU 0 of 25, KR 0 of 5, TW 0 of 8, US 0 of 23.
Item data: MoP Classic client datamine, build 5.5.4.70631. Prices: per-unit buyouts from one Blizzard Auction House snapshot per connected realm per hour; market is the quantity-weighted median of a realm's listings. Retail column: the retail client datamine.
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