I am trying to confirm a bug that may be related to yours. I'm using a Nano, Mavericks, and FTDI drivers are installed.
My Arduino Nano is getting power from USB and is powered up when booting up the computer. It will not show up in the list of serial devices unless I remove and reconnect the device from the USB port. I think the problem has something to do with the FTDI driver being loaded while the Arduino is still in its boot up sequence, but not sure.
Could you confirm that your device shows up after removing and reconnecting it to USB/power.
I'm hoping there's a way to re-initialize the FTDI driver and recognize the Arduino without having to physically detach and reattach it.