When we reviewed the Sony Xperia Z Ultra, it was with the C6802, a HSPA+ model devoid of LTE bands. However, it seems that a speedy 4G version of the handset will arrive stateside soon, if this recent FCC listing is any indication. The document shows what is clearly the Sony Xperia Z Ultra, but with HSPA+ and LTE bands that are more compatible with T-Mobile, AT&T or any of the carriers in the Great White North. This means it's likely the C6806, the handset's North American cousin, all set up to take advantage of the super-fast network on this side of the pond. It doesn't look like there's too much else differentiating it from the international model however, so we'd take a gander at the review one more time to decide if it belongs on our wish list.
Update: We've updated the post to reflect the possibility that this phone is headed to networks other than AT&T.