So, I've seen a whole slew of posts about getting the content off of the DVR, but is it possible to watch content from a USB Thumb Drive or a Firewire HDD? I realize that using a computer independently of the DVR would be optimal, but it's not really an option for me at this point.

Any help would be greatly appreciated.

Unfortunately no. The USB port is not active (it supplies power, but does nothing else), and the IEEE1394 port is only for transferring an MPEG transport stream to a D-VHS VCR (or a device pretending to be one). You can't transfer anything into the unit via either interface, and I don't think Moto has any intent to change that.