We caught wind back in March that Asus was gearing up for a major ultrabook refresh with Intel's new Ivy Bridge chips, and as Engadget reports, they're now official: four Zenbook models will be heading to the US with tentative pricing starting at $799. Specifications for the 11-inch UX21A, and the 13-inch UX31A, UX32A, and UX32VD all line up with our earlier report, including 1920x1080 IPS displays (with options for lower-res screens), Core i5 and i7 Ivy Bridge processors, and 128GB or 256GB SSD varieties. Engadget says that 13-inch models will tentatively start at $999 with Ivy Bridge, but there's no pricing for the smaller UX21A yet, and no release dates for any of the laptops. We'll keep you updated with pricing and release date information for Asus' new lineup as it becomes available.