The 2008 NEC did a pretty good job regarding separate structures, from the same meter, requiring one to be the 'main' and the others 'subs.' That is, every panel after the first needs to have the neutrals segregated from the grounds.
My current job does a fine job of bringing this issue back to life.
Here is the situation: Each of three mobile homes have their own panels, mounted on a post next to each trailer.
The panels all go back to a common board, where each has its' own main breaker / meter. These are fed from a gutter attached to the fused disconnect switch. The PoCo feed is a drop to that switch.
The 'pedestals' are fed from the disconnects by PVC conduit (buried). Service drop is overhead. The disco, gutter, and meter/mains are all steel, with rigid connections.
Disconnect and panel both come with green bonding screws. The meter/main does not - instead, the neutral buss is quite solidly bonded to the case, and the neutral buss has a smaller additional lug (aparrently for a GEC).
Before I tell yuo what I did - I'm not completely happy with my results) - I'd like your thoughts on two issues:
1) Where would you attach the GEC(s), place the ground rod(s)?
2) Where would you bond (or separate) the grounds from the neutrals?
