For prosperity and as thanks to this thread, here's what I did for my 2017 Leaf S:
1. I bought this mirror:
http://www.ebay.com/itm/182228589116?_t ... EBIDX%3AIT
It is a Homelink, compass and auto-dim mirror, cost $75 and can be used with rolling code garage openers. It is a Hyundai part but has no Hyundai or any other logo on it and fits perfectly.
2. Since the wire cover is the short kind and is about an inch short I also bought this longer wire cover (didn't get it yet):
http://www.ebay.com/itm/222086407911?_t ... EBIDX%3AIT
3. It's easy to open the overhead console after reading this:
http://mynissanleaf.com/viewtopic.php?f ... 10#p422867
4. I did have to do some soldering to shorten the harness cable the mirror came with and combine the 2 12V wires that were originally intended to be connected to constant power and switched power.
5. Wired exactly like here:
http://mynissanleaf.com/viewtopic.php?f ... 20#p423048
Yellow - 12V that turns off (verified in my car) after 10 minutes
Black - ground
I didn't know whether the T tap connector required stripping the wire first, know that it doesn't. Just close it with pliers and it's connected.
I did cut a bit of the sleeve the wires were coming out of in the Nissan.
Good luck with yours and thanks a lot for all the posters, I couldn't have done this without you!