I know of the mod adding the block animation when dual-wielding, but the block is actually done with a single weapon. I've tried seraching on the Nexus but had no luck.
To rephrase: Is there an actual animation using 2 single-handed weapons to block? I imagine the weapons being "crossed".
It depends on your definition...
The idle stance animation you see when dual-wielding (the one where you raise one hand in the air) is actually named the blocking stance for dual-wield in the game assets, but the blocking stance mechanic itself is never implemented in the finished product. I found out about it when making PCEA 1.0
So if you're asking "does the game actually has dual-wield block asset?" the answer is yes, it does, only repurposed
If you're asking "does the game has a dual-wield block asset that has never actually been used?" the answer is no, it doesn't
P.S: if you're wondering what the original dual-wield idle animation looks like, I don't know. I don't see anything named that in the game asset. If you're wondering where I found out about it, it's somewhere in the animation group data accessible through Creation Kit (I haven't touched it for about a year no and I don't have Skyrim installed)
Maybe try this? http://www.nexusmods.com/skyrim/mods/9247/?
Though it says it will be a little laggy, I think it is worth a try
If there is, it's unusable since the button you would use to block is used to attack with your offhand weapon. That's the major drawback with using two weapons. You can do much more damage much more quickly, but it leaves you vulnerable as well.
Unless, you're asking if the animation exists regardless of usability? If that's the case, then you'll have to do some digging around around in the animation folder to find that. I don't have the tools available at the moment to help, I'm afraid.
