I don't know if you've seen this doc or not, as it appears in bits/pieces in several places on youtube, but I came across (and watched) a complete version of "The Universal Mind of Bill Evans" today, about 45 min comprised mostly of a conversation between Bill Evans and his brother Harry, also a musician/educator as you're probably aware.

At any rate, I recalled this being referenced in How My Heart Sings, and upon watching it I recognized so many stretches of conversation that I realize it was quoted fairly extensively therein. Worthwhile to see in its entirety, a lot of insightful and intelligent commentary, a condensed summation of his approach to music at the time. His brother as foil appears to make it particularly relaxed; it's hard to imagine any other interviewer saying (paraphrasing), "now Bill I want you to sit at the piano and play exactly as I tell you" and the artist readily deferring. Interspersed with unnecessary bits of Steve Allen reiterating points discussed therein, presumably to make it more accessible - these parts are not overwhelmingly offensive, they just are clearly forced into (and break up the flow of) what is an already fascinating conversation.

I think the musical observations may be of general interest, not just to those familiar with Bill Evans. Lots on creative processes.

http://www.youtube.com/watch?v=Nsnh21ae6YI