Right now Sprint and Verizon use the same technology. Sprint is rolling out wiNMax, which the iPhone won't support and later this year, Verizon will roll out LTE, which the iPhone currently does not support. Even the next model won't support it. It is a waste to go down the CDMA path.
Even with LTE, you will see phones being locked.
Sadly we probably wont see a Verizon iPhone on LTE unless it also supports CDMA. Why? What happens when you happen to wander into a no Verizon LTE area with the Verizon LTE iPhone? You fall back to CDMA, oh wait no you don't you have no cell service at all...