BigB...
Run such issues past your local AHJ.
Because that's who's going to be making the call as to such design specifics.
On the economics, I can't imagine why any electrician wastes his time trying to eliminate bonding or grounded conductors -- for that is what your query is driving at.
There's no money there.... However, there's a very good possibility that your work will be red-tagged if you omit such conductors.
Today's AHJ realize that it is essential for grounded conductors to be bonded to the GEC at only ONE POINT.
Section 250.32 (B) is all about that.
In case (1) the dependent panels in the out-building are NOT to be without GEC systems -- but their grounded conductors are NOT to be bonded there.
In case (2) the dependent panels in the out-building are REQUIRED to be bonded to their GEC systems since in this case only, the isolation of the out-building permits it to be treated, electrically, as if it was an independent Service -- wiring it accordingly.
Case (2) demands conditions that block circulating currents on neutral conductors/ grounded conductors.
The break in design thinking occurred in 2002's NEC.
See NEC Handbook 2005 p 203/4....
