It will be interesting to see what future aftermarket products become available for the Volt.
On the Prius, it went from the CalCars guys hacking one, to several companies commercially making plug-in kits, to Toyota finally making a Plug-in Prius themselves.
Maybe "Battery Pack Enlargements" will become a common aftermarket item?
Who knows!
(I'd hate to get spam for that though. "Impress her with your large battery pack!
)