Hi guys, this bridges Unity and iOS but as its on iPad I thought I'd post it here.
I have an AR project that is swapping real life images for virtual images and on 3GS, iPhone 4S and iPad 2 it's all fine and the images replace perfectly but on the iPad 3 the image I map over the top is slightly smaller than the real life image I replace so you can see it's edges under the AR image I add.
I am using the latest Vurforia version for Unity and an iPad 3 on iOS 5.1.
Lovely, don't forget that the issue also appears on iPhone 4 and 4S, albeit to a lesser extent.