Power sliding doors have been offered in the JDM since introduction of the M5 and are offered in Asian and now (per the Balogna Auto Show) in Europe as well. The JDM delivers 70% of Mazda 5's with power doors but Mazda North America adamantly refuses to make them available here based on an arbitrary marketing decision. Perhaps that will change if they get desparate for sales.
As far as power door conversion, although Mazda North American has muzzled everybody who has had contact with me, I've learned that the door motors would fit the NA version but the wiring would be difficult without a wiring diagram and installation instructions translated into English. If the central control module is involved, forget it.
Although some see power doors as an unnecessary and expensive luxury, it's a necessity for a wheelchair user who can't reach rearward from the front seat far enough to grasp the rear slider. I've exhausted every avenue with MNA and will wait until the marketing boys relent or until another automaker comes up with a similar model with power doors.