A similar talk was given at GTC (GPU Technology Conference), it is S3418: Porting Source to Linux: Valve's Lessons Learned. The video is available for attendees right now. Videos should be available to the general public 30 days after the conference ended. This is the website: http://www.gputechconf.com/page/home.html

This was a talk given at GDC, so it will no doubt end up on http://www.gdcvault.com/ sooner or later - but it will very likely be behind a paywall.