According to iDB, the Verizon iPhone 5 is GSM unlocked, meaning you can pop in almost any nano SIM to get service. This is traditionally used for roaming overseas on international roaming plans, but it is also the first time a CDMA iPhone has shipped with the ability to hop onto AT&T’s network inside the United States. There is no word yet on whether this trick can pick up AT&T’s LTE signal, but it is at least working with HSPA+.
While it is not confirmed, there is a good chance that this will also work with Straight Talk SIM cards—provided you are daring enough to cut it down to nano SIM size. The same goes for T-Mobile’s nano SIM cards.