Mark---by golly, I think you have it! I forgot about the reduced size of the ground wire that is likely to be run! I certainly follow your reasoning in that the ground wire needs to be at least the size of the wire form the "main" panel to the first ground rod.
As for all the homes on the block being served by one rod at one house...well, that kind of ignores the role of the service equipment, doesn't it? My position has been that the 25 ohm requirement, the "system" as it were... is defined as everything served by the main disconnect. Short form- one meter, it's one system.
Now, as for "all the homes...."- oddly enough, we can see something like this in apartment buildings, where multiple meters will be tied to the same ground rod. If it's a smaller building (6 or less meters), then there might not even be a main disconnect.
The 25 ohm requirement is something of a "red heiffer" (for non-bible scholars, I mean "paradox") in the code. One rod needs to met it- but add a second, and there is no requirement for the combination to meet it. I always wondered about that.
The original poster started off saying that , of course, he would have two rods. I see nothing in the code that ever would require two rods anywhere, if the first one meets the 25 ohm test. So that question still stands- why two?
