Thank you for the suggestions so far, I can only really work on one new model however because of time unless I want to spend a lot of time on this.
So far, the Brotherhood seems to be the sword that makes the most sense for Final Fantasy, however, I'll probably just find a model online for it instead which means I'm interested in creating at least one more model.
The weapons that exist in the game with slight variations I don't have any interest in doing because they too closely resemble something already in the game. The Soul Edge and Soul Caliber are pretty crazy looking weapons which are too big of a task for a simple mod I think.