In fact, all of these weapons may have common ancestors. My hunch (and it is ONLY a hunch) is that Smith did indeed get his taste for such weapons through his travels. Imagine the variety of arms and armour he must have seen in action! Whatever we call these weapons, I think the important point is that Smith recognized their value and used one himself. That's quite an endorsement.

And speaking of different blade types in Italian falchions, take a look at Nathan's post in the Off-Topic section about "Armi Bianche Italiani". On the right you'll find a falchion page with 6 different hilts, 6 different blade types.

The next row up, on the left side, there's a crossguard that looks very close to the one in the Smith engraving.

You could combine a pommel like the one at the top of the page with a crossguard with scrolled ends with a blade with a clipped (Bowie) tip, and have something that is at least historically plausible.

--ElJay