I looked through the latest alsa configuration docs online, and it looks very good. Great job! One little suggestion: I think that there should be instructions to install the alsa-oss package (provides OSS compatibility) and alsa-tools. Maybe it would be a lot easier if it simply had the line: emerge alsa-lib alsa-utils alsa-oss alsa-tools that would install everything in one shot.
Fixed in CVS. //ZhEN