Training Documents from Verizon that confirm that they now offer native dual stack IPv6 services on AS701 (legacy UUNET) in 38 pops in the US. This includes the POP in Houston and Dallas. If you are a current Verizon customer with a circuit that terminates in one of those POPS, contact your sales person and find out more.
In related news, Verizon Wireless has stated (as recently as the most recent CES) that they intend to support IPv6 with the LTE network. However, it is not clear exactly when that will be available.