I can not see Apple a Leader in Technology making a CDMA iPhone for it only to be used on CDMA for a year or two then it will not be ready or able to work on LTE, seems like someone is talking out their butt hole.
If they ever made one, I am sure it would have to work on future networks and GSM, I can not see them leaving this feature out, LTE is around the corner and who know how it will even work, personally I do not think you will see that many improvements only because all Cell providers are pushing people towards monthly data plans and smartphones thus pushing data usage up even higher.
If they ever made one, I am sure it would have to work on future networks and GSM, I can not see them leaving this feature out, LTE is around the corner and who know how it will even work, personally I do not think you will see that many improvements only because all Cell providers are pushing people towards monthly data plans and smartphones thus pushing data usage up even higher.