An apparently reliable source at Palm has told TechCrunch that Palm is “very far along” on a second, smaller Pre-like device to be marketed as soon as this fall, 2009. Pre nano, anybody?

Details are scarce, but the device is rumored to be both smaller and thinner than the Pre, which may mean we’re looking at a phone with the QWERTY keyboard replaced by a soft keyboard. It is assuredly not the “Pre 2,” since it’s too soon for Palm to be this far along on that project, but it will run Palm’s ballyhooed WebOS.

The main factor here seems to be the device’s size, hence TechCrunch’s moniker “Mini-Pre.” We’ll keep you updated when and if more info comes in on this mysterious Palm project.