According to the updated screens support developer documentation for Android for Android 2.3 Gingerbread. This means support for big screens, officially up to 10".
'xlarge' targets screens better 7" and 10".... starting in Android 2.3, the platform includes support for extra large screens (xlarge).
Though the supported resolutions list has not been updated, it is likely that 1280x800 is one of these newly supported recommended resolutions for developers. This is new developer guidance for testing existing applications for high resolution screens.
Now that Android is more or less 'tablet ready', it looks like Samsung's close partnership with Google will make the Samsung Galaxy Tab (at 1024x600 and 7") the first standard Android 2.3 Gingerbread tablet.Devices with extra large screens are tablet-sized or larger, so you should pay close attention to how usable your application is on such screens. You might want to design new layouts specifically for extra large screens, to address usability aspects such as the location and size of buttons in your UI. To test your application on an extra large screen, create an AVD targeted to Android 2.3 with a high resolution, such as 1280 x 800, and the default density of 160dpi.
Will other tablet manufacturers who have already released their devices now follow? My speculation is that many manufacturers, large or small, will continue to ignore Google Android development guidelines and release their devices with outdated versions of Android anyway. Are the features of Android 2.3 enticing enough for consumers and manufacturers to care, or will they turn a blind eye?