Krupski:
Buy yourself a Duemilanove. It's an Uno with the FTDI serial interface chip
I already have some Nanos on the way. I was just trying the FTDI board with the Uno in the mean time.
I would think that holding the 16u2 in reset would tristate the outputs as well. It certainly does keep the Uno from showing up as a Com port in Device Manager. I tried the TX/RX lines swapped both ways and in either case, the Uno is not seen via the FTDI board.
I guess I'll just have to wait for the Nanos.