Doubtful. In all my screwing around with every console command available, I've never found it. I think there's something in the code which restricts it.
I just have to ask though... Why? Using the saber in first-person stops you from doing dodge moves such as rolls and flips, so you're practically a sitting duck. >_>
I don't know how, and I don't know why, but this is totally Sheep's fault.
There may be some mods that modify the camera a bit to do that. Otherwise I think you can change the cameras a little bit until you find what you like.
Also I don't exactly recommend 1st person with the lightsaber. Seemed a bit difficult to work with in my opinion.
If cheats are on, you can use some third-person zoom command (I forget the exact call; sorry) to quite accurately replicate first person.