We solved our own problem of saving for iOS from Photoshop. Same idea as Save for Web but optimized for retina and not retina screens.
Build your art at @2x, run the script and it will output the full document at retina with the suffixed @2x in the file name. Then a half size of the image for non-retina displays is saved.
You can get the file from the attachment or just right click Download Linked File here.