Even though replacement keys have been recently talked about on a number of different threads, I couldn't find a thread dedicated to this topic so I thought I'd start one so we could find the information in the future. For example, My third i-MiEV did not come with a spare key and since we make it a habit of leaving the keys inside the car (unless we're in town) I became a little nervous at the prospect of inadvertently being locked out or something going wrong with our primary key. 
eBay sells blanks ranging from $10 to over $100 - but what do I know? Called up the local key shop about a replacement key and they said "sure, no problem, just bring in your car and key". Not being ambulatory at present, I asked my wife to stop in there and get a replacement key made.
She came back and allowed as they made her a replacement key for $63 and that it works to open the door and works in the ignition and the car operates just fine with this new key, but it is missing the buttons. Presumably there is a chip in the key handle that the locksmith matched to the car.
I took the primary key far far away and confirmed that the replacement does indeed function as a stand-alone key. It will simply be stored in the house with all my other spare keys. Better than nothing and better than a dumb key that only opens the door, and certainly better than Mitsubishi dealer's price, for simple peace-of-mind. Don't plan on losing the main key with its buttons.
As an aside and way off-topic, I haven't removed the key from the ignition of my (presently mothballed but running) 1967 Saab in over 40 years - never lock the car (nothing inside worth taking), have a separate pushbutton starter button, and never worry as -
1) Who would steal it? :roll:
2) Even if they figured out how to start it, they would never figure out the column-mounted gearshift (especially reverse). :twisted:
Still off-topic, I can't help but wonder how all this fancy theft-proofing on the i-MiEV will work after 50 years?... it's struggling with stuff like this and difficulty in hacking cars' software that makes me think that present-day cars will never survive to become 'classics'.
Be interested in others' experiences with obtaining replacement keys.
