Occams Razor

So if you have the ability to wield a Long and Small Weapon, is it possible to dual wield a Small and Small Weapon? Like two Butcher knives, two shanks or two steak knives?

Two very important points:

1) Unless otherwise stated, a weapon skill allows you to use a specific weapon or combination of weapons. Weapon skills do not have a subtext of "and all equivalent or lesser weapons."

2) Small weapons should really be used for defense only. Small weapons are pretty darn small, and it's easy to accidentally punch somebody. Moreso when you're flailing around with two of them in a field fight. That's not to say you can't deathstrike with them or tap somebody on an outstretched arm or use them for a stylistic takedowns from behind. By and large, though, they're meant for blocking. I'm fairly certain everybody in the game can use a single long--go with that. It's much more effective anyway.