In case you had not heard, the proprietary Qualcomm CDMA system is nearing a dead end, with the last CDMA networks having announced they would go to GSM/LTE for 4G.
In Canada, Bell and Telus have already begun to retrofit their towers to support GSM-3G. (HSPDA). My guess is Verizon is doing the same and may be able to support a native iPhone without requiring Apple make a CDMA specific iphone.