Well I never knew that Martin Landau was approached to play Spock before Nimoy. He says so in this interview. He also shows that he has no love at all for producer Fred Freiberger. The special's host looks just like Boxy from the original "Battlestar Galactica".
Space:1999 - Martin Landau interview (1999)
Martin Landau is interviewed about Space:1999 for this French program from 1999. While the clips and narration are in French, Mr. Landau's comments are in English.