I guess Davide is referring to the AVID AUDIOVISION, which was Avid's DAW before they bought Digidesign and Pro Tools ruined it.
To answer your question first: I'm sorry, but I don't know any video online and just had a look and couldn't find any manual or stuff like that anymore. :-(
But I still know one or two studios who still have a working system. (But only for backup compatibility)
For me AudioVision was the first DAW I worked on. I learned everything film related on it and am happy to have done so, as I still think it was a lot more focused on EDITING sound and not just track laying and mixing.
E.g. you could select all the scene edits of a reel and then say you want a 2 frames crossfade centered on the cut. Not speaking of bins with subsequences (great for editing changes, or pasting the basic ambiences of a scene) or the clip editor for selecting the material and channels you need prior to putting it in the time line.
Also as you mentioned clipbased gain and a bunch of other features never made it into ProTolls though some were announced to make the transition.
But I can also say that with todays mixing, multichannel and Plug-In capabilities, I would not want to trade in a recent ProTools for an Audiovision. (Though for foley editing it should still be faster to get the job done - IMHO)
Let's see where the future development will lead us. As long as some people have not forgotten about the benefits of such a system the ideas are still vital. (hopefully)