I built oscar's S/PDIF interface exactly to the schematic, with some additions to it. The Toshiba part is obsolete and hard to find, so the only place I found it was on parts.pioneer.com for $45. Quite a bit. I did use a cheaper modern Cirrus Logic part but never got it to work. I added coax S/PDIF output as well as S/PDIF output over an RS485 transport. I connected the TTL signal to an RS485 transmitter with a receiver at my DAC. I'm able to transmit S/PDIF 100ft using a crappy 100ft phone extension cord, still sounds great.
Now, how well does it work? I cannot say enough how well it works and what a genious oscar is. It runs off 12V from the digital av connector. The regulator runs super cool as it doesn't draw any power at all, even with my additions. When the audio bus pins on the wii are figured out it'll work with the wii too. I've included some pics of the interface.