AT&T has announced that it will offer Wi-Fi + 4G models of the third-generation iPad starting on launch day. According to the announcement, all models of Wi-Fi + 4G will be available, across all AT&T sales channels. “The new iPad is coming to the nation’s largest 4G network and we could not be more excited,” said Ralph de la Vega, president and CEO, AT&T Mobility. “Our customers will get a widespread, ultra-fast and consistent…