We list the wrong sizes for the four iPad splash screen graphics on http://docs.appcelerator.com/platform/latest/#!/guide/Icons_and_Splash_Screens-section-29004897_IconsandSplashScreens-iOSgraphicassetrequirementsandoptions
The correct graphics are noted in this link to the TiCons project:
Apparently we're not supposed to omit the height of the status bar, which ours do.
While we're at it, we should note that the iTunesArtwork and iTunesArtwork@2x graphics are needed only for development and AdHoc builds. They serve no purpose in production/AppStore builds and should be removed before you build & submit your app to the iTunes App Store. (Otherwise they're just making the IPA bigger.) See https://developer.apple.com/library/iOs/qa/qa1686/_index.html for a reference on that. The Titans and I tested with an app published without those files and the icon still appears in the iTunes desktop app (for syncing).