Thanks a bunch everyone for your input!
The player wanting to do it sees this as a long-term plan, hoping to present the new Sword to Luccio and thereby getting in to her (and the rest of the Wardens') good graces. As such, I feel it would be fun to make it into something that is actually played and not just "off-screen", so to speak.
Based on the input, I think I've come up with a reasonable way of doing it.
Phase 1: Identifying the Sword
Weapon:3 examples seem to be around Good (+3) in the Buying Things table. Seeing as this is specialized equipment, I bump the cost one more step: Great (+4).
Phase 2: Assembling a workshop.
Crafting a Great Sword requires a Great Workshop. Assuming the Resources skill of the Crafter isn't Fantastic (+6), they do not have such a workshop automatically. Thus, a roll is required. Declarations on Contacts, Burglary, etc could likely be used. Assuming Time Required is similar to building stuff, this would take 1 month (1 day +4 steps), with no shifts spent on reducing the
Roll: Fantastic (+6) Resources.
Time: 1 month
Phase 3: Crafting the Sword
This is pretty basic. Great (+4) item requires a Great (+4) roll on Craftsmanship. Declarations on Craftsmanship (by another crafter), Contacts, Resources could likely be used. Time required would be 1 month. Positive and negative shifts can decrease and increase this time, respectively.
Roll: Great (+4) Craftsmanship
Time: 1 month
Phase 4A: Enchanting the Sword.
The sword has 2 enchantments: Fantastic (+6) attack and Fantastic (+6) Counterspell, usable 3 times/session. Since the Sword uses two enchantment slots, I would assume that both spells are baked into 1 enchantment and that the extra two uses come from the second slot. Thus, 6 shifts towards the first spell, 6 shifts towards the second and 1 shift to add "usable by others" to the Sword.
Complexity: 13 shifts. That's one hell of a Lore requirement.
Time required: Super long.
Phase 4B: Enchanting the Sword
The sword has 2 enchantments: Fantastic (+6) attack and Fantastic (+6) Counterspell, usable 3 times/session. These are assumed to be split in to two enchantments, since the Sword uses two Enchantment slots.
First enchantment (Weapon:6): 6 shifts for Power, 1 for "usable by anyone", 2 for two extra uses/session.
Second enchantment (Fantastic (+6) Counterspell): 6 shifts for Power, 1 for "usable by anyone", 2 for two extra uses/session.
Complexity: 9 (x2)
Time required: Long (x2)
Any and all input, thoughts and comments are highly appreciated.