Guild Level 10

The cloaks cost 1200g and appear to require at least honored reputation with your guild to purchase, in addition to your guild reaching level 10.

Probably the best enchants for these heirloom cloaks:
Enchant Cloak - Superior Defense + 70 armor
Enchant Cloak - Dodge + 12 Dodge (this is the harder to find Ahn'Qiraj version, not the Lower City Exalted version which requires ilvl 35)
Enchant Cloak - Lesser Agility + 3 Agility
Enchant Cloak - Stealth from Ahn'Qiraj or
Enchant Cloak - Stealth from Cenarion Expedition Exalted
No good enchants for the caster cloak :(

if you have one toon in good standing you can buy them and distribute as needed. However at that point i would also recomend putting that toon in your guild as well so you can get the fast track bonus.