Apple is unlikely to distribute more than one iPhone 5 model across the same territory which means that Verizon and AT&T customers will almost certainly have the same handset, albeit locked to each network.
This decision could be motivated by the fact that it would be more expensive and would not allow it to shift more stocks quickly within the same geographical location;
Qualcomm is more than likely to be the company manufacturing the baseband for the Apple iPhone 5 after Intel acquired Infineon; this means that a CDMA/GSM baseband like on the Qualcomm Snapdragon MSM8660, is almost certain to happen.
The MSM8660 supports the following wireless technologies: GSM, GPRS, EDGE, UMTS/WCDMA, HSDPA, HSUPA, HSPA+, MBMS, CDMA2000 1xRTT, CDMA2000 1xEV-DO Rel. 0, CDMA2000 1xEV-DO Rev. A, CDMA2000 1xEV-DO MC(MC-Rev. A), CDMA2000 1xEV-DO Rev. B
This making the chipset a true global phone with the notable exception of TD-SCDMA support in China; a similar approach by Apple will mean that a single chipset may cover all territories except China and be used across more than one platform (iPad 2, iPhone 5 and iPod Touch and Apple TV).