Check out the 2012 GURIEC National Video Interpreting Symposium which lists some presentations about VRI. These links show the YouTube presentations but many of these also have PowerPoint presentations in a separate link.
Scroll down to 2012 National Video Interpreting Symposium to find these presentations I listed below.
A Study of VRI Mediated Interaction in Australia
What if the TV Really is Talking to Me? VRI in Mental Health Settings
Consumers and VRI
VRI Best Practices
Interpreting via VRI in the Medical Setting
Inova Health System and VRI