OP is right currently there are no tanking mods available from merchant. i think people are a bit confused when they say "mod" so ill break it down... theres 3 slot in ur gear armor mod enhancement armor- there ARE armor tanking mods like guardian armor mod- there are NO tanking mods only dps and what every other class would be enhancement- artificer so im not sure what they can make. Gotta check vendor. The only way i can think of to get tanking MOD is to get one from a quest or token vendor and RE that and hope get the recipe