You had to know it was only a matter of time. Engadget is reporting that the HTC HD3, successor to the HD2 (and previously the HD), will be launching on October 18th. The rumor stems from leaked internal documentation reportedly from UK carrier O2. If the document is to believed, the device will be named the HD7, possibly to correspond with the Windows Phone 7 platform.

Our guess is that this device would carry the torch as one of the flagship devices for the platform, much the same way as the HD2 has been. We’d love to hear some of your thoughts in the comments.