T-Mobile customers may lack 4G LTE, but if the latest rumors are right, it'll be the first U.S. carrier to offer its customers a quad-core smartphone. Related storiesHTC One X reviewHTC One S reviewHTC One V reviewThe HTC One X+, suggests TMoNews, will carry Nvidia's Tegra 3 quad-core processor, the same chipset used in international versions of the HTC One.The U.S. versions...