Nope, they're on small proprietary chips that are removable. The MBA's SSD isn't soldered in either, it's the exact same style as the new MBP's but a different connector. Only the RAM is soldered in in both models.
Oh okay. Then I'm definitely getting the base model of the new one, and I'll upgrade to 512gb once an upgrade is made available. I believe Other World Computing has 768gb SSD's for the MBA, they'll probably make a 1tb one for this thing.