Stage 1 complete: you can now get an access log (in Common Log Format) by setting "server.logAccessFile" to some writable filename. The old log has not changed; stage 2 will probably be to remove access messages from the old log file, and only use it for errors/config.
Screen output (if enabled) includes messages for both logs, just mixing them as they arise.
The only major bummer is that I violated the CLF spec a bit--if there's no "Content-Length" header (as in a pure HTTP/1.1 conversation when content is yielded from a page handler), then there's no number of bytes in the response body. I had the logger output "-" in that case, which actually signifies no body. The alternative seemed worse (violating Peter Hunt's nice isolated WSGIServer by making it write to CP's log).