There is no such thing as an "Unlocked" CDMA device. With the 4S and 5, carriers have the option of unlocked the GSM portion of the phone. Verizon and Sprint will do this for customers in good standing, but only for International GSM carriers.
The only way to get a CDMA iPhone is from a US CDMA carrier or from Apple. There will not be an "unlocked" CDMA iPhone offered as no such device exists.
If and when an unlocked iPhone 5 is offered in the US, it will most likely be the unlocked version of the AT&T model.