This PND allows you to access files on e.g. modern Android phones which no longer support mass storage mode, but understand the media transport protocol. jmtpfs is an implementation of libmtp using FUSE.
In order for this to work you need to make sure that your
1. device's screen is unlocked
2. Pandora's USB host mode is enabled
Note: Some file operations will take longer than expected. To change a filename the program must make a local copy of the target, rename it and then copy it back to the device.
Please give it a whirl and report back! Does it also work for iDevices?