Well, since I've already been offered a line on my first request, let's give this another go. Two other Roddenberry-related 1970's-era efforts are also on my want list. I think I may have found a source for the first, but here is the info anyhow:
Spectre was a 1977 telefilm produced and co-written by Gene Roddenberry as the pilot for a proposed weekly television series, but it was rejected.
William Sebastian (played by Robert Culp) was a criminologist who had taken to studying the occult to explain the problem of human evil. He had apparently been cursed on one of his adventures, leaving him in constant need of medical attention. Sebastian's colleague, Dr. Hamilton (played by Gig Young; who sadly committed suicide shortly after filming ended) was called to his home to help him and the two were soon summoned to England to investigate strange happenings involving a mysterious Satanic cult and the demon Asmodeus.
The relationship between Sebastian and "Ham" was deliberately reminiscent of that of Sherlock Holmes and Dr. Watson, although there are also aspects that recall the relationship between Roddenberry's earlier Mr. Spock and Dr. McCoy (Roddenberry previously revisited this relationship in another failed pilot, The Questor Tapes). The movie also featured Roddenberry's wife Majel Barrett in a supporting role as Sebastian's housekeeper Lilith, a practicing witch (she brewed a remedy that "cured" Ham's alcoholism through aversion therapy).
Spectre was one of many unsuccessful television pilots during the 1970s that were set within the occult detective sub-genre. An extended version of Spectre was released in the United Kingdom as a theatrical film with additional footage that included explicit nudity in the black mass finale.
The Questor Tapes was a 1974 TV movie about an android (portrayed by Robert Foxworth) with incomplete memory tapes who was searching for his creator and his purpose. It is believed that this project inspired the character, Data in Star Trek: The Next Generation and from all indications it is not currently available in any format.
Any help in locating "watchable" versions of these forgotten movies would be much appreciated.