If you've seen what Wavebend can do with the files, its possible to do a lot of crazy stuff including turning someone into a box. As for the sword, I also put the Heartwood Staff in that post with its statistics after your first commentary, the only changes that would need to be made are what masterwork properties are acquired and based damage changes (was considering going with Fire because we don't have a high end one yet, or as a staff that works on the Mark of the Riff property of having all three damage types and either striking a single target three times per shot or randomly determining what the element is each swing). I didn't cover a 2h weapon or a dagger but I could work up a mock weapon set.
Also in reference to Spirit Blade, it has to have a hilt that also appears in the person's hand so during the time of the Spirit Blade animation you may theoretically be able to have him off-handing a normal sword with that swing animation.
I'm not totally sure we understand what each other is trying to say.
I haven't really looked into how the game is coded, not do I really have more than a basic understanding of it anyway.
However, my concern with your idea to have multiple classes using a sword is that it might not be possible for the game to be changed that way.
Spirit blade probably never has the game think that your character is actually holding a "sword." It still thinks your character is holding a staff, but the animation and graphic are changed.
Silent sister is intended to be a dagger wielding warrior, but it seems like the developers couldn't find a way to have warriors hold dagger or for a rogue to open a warrior door.
This may be because warrior HAVE to wield one hand swords. (It's probably likely that there are actually 5 "classes," even though we think of them as 3. 1 hand warrior, 2 hand warrior, bow rogue, dagger rogue, and Mage).
If my guess is correct, they could never make a Mage wield an actual "sword." They could make a staff, call it a sword on the in game description, make it look like a sword, and give it a swords animation, but it would still technically be a staff. And in that case, a warrior couldn't weild it.
Maybe I'm totally off here, but that seems like it might be true given the issues they've had with Pala.