Just wanted to let folks know about the MNL thread on this very topic (reset degraded battery from 9 bars to 12).
http://www.mynissanleaf.com/viewtopic.php?f=4&t=18539&hilit=replacement#p400125
If I were in the market for a used Leaf, I would be VERY careful right now. It sure seems like someone (probably Nissan) is making a concerted effort to move used hot weather Leafs to cold weather climates (Norway, MN).
I hope I didn't imply too much with this post. The battery reset issue is different than the movement of hot weather Leafs to cold weather locations. In the former, there may be very few instances where the battery was reset (whether intentional or not, it is hard to know). In fact, I have only read of the one cited above, so it might actually be the only one. However, the latter issue (transfer to cold weather environments) is more widespread and is a simple way to slow battery degradation before reaching 8/12 bars. Yes, the dealer in MN may be very interested in selling EVs and buying used Leafs at auction for $8-10K and selling them for $12-14K may be all that is happening. However, as I said, just be careful and check the battery with Leaf Spy.