Replicating Tx and Rx LEDs In my application all of the Arduino Uno LEDs will be invisible inside an enclosure, so I wish to provide panel-mounted Tx and Rx LEDS just replicating their on-board counterparts. Is there a way to drive any of the digital outputs to replicate those LEDs? I seem to recall that the Tx and Rx LEDs are driven directly from the FTDI logic, does this preclude hacking their states and sending them to two digital outputs? How could this be done? I could de-solder the LEDs and hardwire the panel LEDS to their pads, but I think this should be a last resort.
The USB to serial and LEDs are done with the ATmega16U2 (the chip near the USB socket). 

If you look closely you'll see there are 4 pad near the chip, JP2 in the schematic. You could solder some wire to it to connect your leds. You could then slightly modify the firmware running on the ATMega16u2, and upload it using DFU.

I did this on my arduino uno to break out the reset signal, so I could use my UNO to program an separate ATMega328 over serial.

In your case you could use the pads connected to PB4 and PB5 (as the original code uses PD4 and PD5), so the you only have to change DDRD and PORTD, to DDRB and PORTB in LED.h.