I mentioned in a previous article that dual-core processors might be coming to Android — a first for smartphones.

According to a source, AndroidGuys’ Scott Brown says that T-Mobile’s somewhat thin offering in cutting-edge Android devices is about to change.

A recent leak may indicate that T-Mobiles Android lineup could not only put them back on top in the Android game, but could also be a major milestone in smartphone technology: the introduction of a dual-core smartphone.

According to the unnamed source, at the recent HTC Seattle event, a group of T-Mobile employees leaked the details of an upcoming Android-powered device.

If true, the device will likely feature a 4.3″ screen (similar to the EVO and Droid X), the “Gingerbread” version of the OS (which some refer to as “Android 3″), and an 800 MHz dual-core processor. While 800 MHz doesn’t sound all that impressive (the Nexus One runs at 1,000 MHz), what is impressive it that there would be essentially two 800 MHz processors in the phone, theoretically 1,600 MHz of processing power.

If the rumor is to be believed, the phone could launch around the 2010 holiday season, which coincides with what we’ve heard regarding Gingerbread’s timeline.