Verizon Wireless confirmed that it has more than 500,000 subscribers using its 4G LTE network. The HTC Thunderbolt, which launched as Verizon’s first 4G LTE phone, is responsible for 260,000 of those subscriptions. The wireless carrier said that it added about 500,000 4G LTE customers this quarter in addition to the 65,000 early adopters who signed on in Q4. Big Red will continue to build out its 4G LTE device portfolio in the coming months. In addition to the HTC Thunderbolt and Samsung DROID Charge – announced on Thursday – it has plans to launch 4G support for the XOOM, an LTE version of the Samsung GALAXY Tab, and the Motorola DROID Bionic later this summer. It also currently offers three 4G LTE USB modems and two 4G LTE hotspot devices.