It exists; we saw it for ourselves! Wadia's $349 iTransport can take the digital signal out of an iPod before the DAC, outputting 16-bit/44.1khz resolution for uncompressed files—it doesn't upconvert lower-rez files like MP3s, but it does reformat them to 16/44.1, according to Wadia's John Schaffer.
We ran into SinglePower Inc.'s Mikhail Rotenberg as he was sprinting down the hall to the Synergistic Research room. "Check these out," he said. "These are a 1932 Tung Argon 4327 and a 1943 722A (323), labeled Centennial, but manufactured by Western Electric."