You may not believe it, but ACM Hypertext and Social Media conference maybe just he place your your HCI and/or Accessibility work. With average downloads per article running at 384 and average citations per article at 6.87 (according to ACM bibliometrics) this 100 person conference is comparable to CHI.
As promised an attempt was made at an ACM ASSETS 2012 Live Stream. There were two streams one of the Keynote and One of Session 1. Here are the archived versions.
So we are coming very close to the W4A Paper deadline for the 2011 edition, indeed, it is on the 10-Jan-2011.