As far as I know there is no such code requirement. If the GEC is connecting an array on the roof to ground in only one place , I can't see what difference it would make and I would say it should be allowed.
However, if it is coming from a ground mount I believe it would be a terrible, terrible idea in lighting prone areas. Also if it acts as a bonding jumper between electrodes on opposite sides of the house I believe it would be a terrible, terrible idea. (IOW, don't put your 690.47(D) electrode on one side of the house and then put the DC conduit and inverter, connected to the AC GES, on the other side.)
Why do I think this? See this video from the host of this forum:
http://www.youtube.com/watch?v=YuDqXFvRv94
Ask your AHJ to watch it too.
In my opinion, 690.47(D) is itself a terrible idea.