Not "designed in", but a LEAF-rescue-LEAF is one of the things on
our to-do list. A QC port, at least in Japan, can be used to power
a house from the energy stored in the LEAF's battery pack.
So, if the USA version is also capable of that car2home operation
(that is, negotiating with an external "QC" type device to allow
energy to be taken out of the battery pack), then a "Share-QC"
device could be designed, with two Jolomo type mini-QC plugs,
and sufficient electronics between them.
This would be basically a DC powered mini-QC unit used to charge
the "recipient" car, and a "Share-QC" controller for the donor-car.
The DC powered mini-QC should be an easy variation of the AC
powered mini-QC that we are experimenting with, and the
"Share-QC" controller should be easy, once we discover the
car-to-home protocol... all assuming that the USA version of
the LEAF is car2home capable, of course.
When a suitable, reliable network of QC stations is available 24/7,
there would be less need for such a device.