Well this is just one of those things thats [maybe] easy to implement to the game.
And now to the point. IMO you should be able to make superior weapons from vostaskus as the game atm lacks those lategame kinda like "status symbol" items.
These weapons should work kinda like valyrian steel weapons in GOT, the prized heirlooms of a guild that only the mightiest of warriors should swing around.
Well and now to the stats: to make these swords kinda useful and balanced at the same time the cost should be astronomical but the DMG it deals should also be like 2 or even 3x the dmg normal swords deals, so the costs of the sword(s) should be something like 4ingots for 1h sword and 6ingots for 2h swords, just for these to be the really endgame items to the guilds when the guild has the lvl 4 monument and the blacksmith with 100 skill in forging.
And a little bonus: Just to make these weapons unique they should have the option to name them and some unique colour pattern in the blade and the hilt should be some some what different from normal swords.
Just imagine the faces of some dirty peasants when you ride into their little farm with one of those big 2h vostaskus steel weapons of your back.