I don't know who put this together or who uploaded it to YouTube - it looks like it's assembled from bits of interviews that we did for the eventual Exeter "special features" - but while looking over there for an old Starship Farragut trailer with Don LaFontaine's voice-over I found this mini-documentary about Exeter:
EDIT: Looks like it was uploaded by Stan Ginsel, one of the producers. I don't know anything else about it.
What a find! I've been looking forward to seeing the "making of" documentary almost as much as Act IV. (Emphasis on almost