Sorry to hear of your accident. It's never fun.
As for Leaf rentals, Connell Nissan at one time was renting out Leafs and
had a discount for MNL members and/or Facebook 'friends'. If you haven't already, you may want to ask them if the discount still applies and if a Leaf would be available for long-term rentals(*). Wouldn't be the same as driving your "Leaf Now", but it'd be as close as it gets.
Also, I would 2nd the recommendation for Caliber Collision Centers, especially if the work is being done through insurance. Seeing as yours was a rear ender, I take it their insurance will be picking up the bill. We've used Caliber twice through insurance work, and once for non-insurance work (
though not from shops below). They did quality work each time.
Looks like the near-to-you, freeway close
Anaheim Caliber Collision has pretty 'stellar' reviews on yelp.
Even their
Costa Mesa shop has solid reviews.
The
Euro American Collision Center in Costa Mesa has mixed reviews.
EDIT: (*) In hindsight, maybe not for as long as you may need it since they probably just do it for extended test-drives. It wouldn't hurt to ask, though.