It can be unlocked for international GSM/HSPA+/LTE networks, so your best bet would be to ask Sprint to unlock it, and then sell it. And buy a Verizon iPhone 5 from the proceeds.
Technically, the hardware for both types of phones are the same. Unfortunately, both Verizon and Sprint have made policy decisions where they will not allow phones from other carriers on their networks, even if they sell the identical model. If the MEID of the phone doesn't match up with their inventory, the activation system will refuse to provision the phone. There is no override for this.