I just got my new 7" screen and it looks great. You did a great job on the layout I might suggest that you put the connector for the arduino in the center of the display, but I am nitpicking.
To test the new display I modified a little program I made for the 4.5" display. I ran into a problem on the right side of the screen. It appears that when the sprites that I am using go beyond about y = 600 the sprite does not display on the screen. I am using the readout from the serial port showing touch screen coordinates.
I assume that there might be a some parameter that I am not setting. I am sending the Code and the Sprites I am using.