Homeseer Technologies is working hard on a native iPhone version of their HSTouch client, which already runs on multiple platforms.  The HSTouch designer will support creating the screens, but due to platform differences, there might be an initial limitation to the fonts you can select and other minor cosmetic differences.  It will support both local (Wi-Fi) and remote connections (3G).  ETA or pricing information is not available yet.

Once I have more information and screenshots, I will post an update.