Who crafts Red Mage Arms?

[KurohNeko]

I was wondering if Blacksmith can craft Red Mage arms, or if they even have craftable weapons?

[Jojoya]

I think Goldsmith makes all the crafted RDM weapons with the exception of the Tremor Foil.

[Caimie_Tsukino]

I don't recall Blacksmith being able to craft any RDM weapons. Just as Jojoya said, it's mostly GSM.
I am not sure if you meant "if Blacksmith even have craftable weapons" or "if Red Mages even have craftable weapons".
If you were asking if BSM is able to make craftable weapons, the answer is a big YES, as BSM crafts weapons for most of the battle jobs, including PLD, WAR, DRK, NIN, SAM, MCH, and occasionally MNK, DRG and BRD.
If you were asking if RDM even have craftable weapons, the answer is also a big YES, as GSM makes many, many craftable weapons for RDM.
Keep in mind that most of the really pretty glamor weapons would be locked behind Master Recipes, so you do need to acquire the Master Books to access them.