Single username/password for any platform?

Is it possible to give someone a single username & password that the person can use to login via WPA2-Enterprise from any type of device? (Android, iOS, Mac, Windows, Linux, etc?) I would prefer to not have to distribute certs either, and it's OK if the user has to accept a self-signed cert on first connect for each device. I've been googling this and can't seem to find any discussion that has a single cookbook cross-platform example, so I'm thinking it might not be? For example, my Android device just asks for an EAP password, and not a username/password like Windows does. Thanks...