Jim, you bring up an excellent point of what Blackbeard's sword probably really looked like in the form of a clipped falchion such as this one-
http://www.thomasdelmar.com/Catalogu.../lot0113-0.jpg
When we look at Fernando's pic of Blackbeard above, created around the same period, note the hilt is of the grotesque animal head type. We've discussed the Houndslow type, which probably mimiced some of the early Dutch pieces, which possibly took their forms from kastanes (the Dutch EIC being in Ceylon during the Anglo-Dutch Wars certainly influenced some of their sword styles). Here are a few of similar type and of the period Blackbeard might have taken a liking to...
http://www.thomasdelmar.com/Catalogu.../lot0120-0.jpg
http://www.thomasdelmar.com/Catalogu.../lot0114-0.jpg
Here is a similar style to the one found, but in silver and last quarter of the 17th century, no quillon hole-
http://www.thomasdelmar.com/Catalogu.../lot0124-0.jpg