With two retainers with 8 bag slots and the ability to store 10,000 * 3 of each shard type. I haven't come up with a reason to need an alt yet. But I don't have tons of crafters to 50 so I don't know. But why to you need to mule stuff with as much space as this game gives us?

Housing will likely solve the problem by allowing us to store stuff in furniture but it won't be out for a long time.