That's probably the highest shipping configuration they can do with striped SSDs (256GB each). So if you were in the US and were able to customise your Y5070 order, 512GB striped drives would be the highest-end option you could pick. You can stick larger drives in there, it won't be a problem.
Thanks for the confirmation!
I've been using the laptop for a while now, and while I still haven't played many demanding games, it runs everything I throw at it fairly well. The built in speakers are surprisingly decent as well, but won't replace dedicated speakers, obviously.
The hard drive can be sluggish though, especially noticeable copying files to and from a USB 3 external. On my desktop with faster drives it would copy on average at double the speed as this laptop.
I will check back in when I get my SSD but that will probably only be in a few months.
@hsark, right now my battery life is around 3.5 - 4 hours non-gaming, which isn't great, but I'm rarely far from a power source so it's been fine for me so far. An SSD in theory should help with the battery life