For the producer of an upcoming PBS documentary, "America in Primetime," Philadelphia's Bill Cosby is one of a few really big ones who got away.

Not that Cosby actually ever said no to an interview.

"We never quite got to him. But Bill doesn't do these things. We talked to people who talked to people who talked to him," including  Cosby's personal rep, David Brokaw," Tom Yellin said this weekend.

"He's [Brokaw] very kind. He just said, 'He doesn't do that,' and I understand, and it's OK. But "I'm really proud of how we treat" "The Cosby Show" in the series, he said.

"What was meaningful about ['The Cosby Show'] is not that he's a black man or that it's a black family. What's meaningful about his show in the arc of dads on TV is he seized control of the house. That's really what he did. And that's what we focus on. In fact, we don't even mention his race, or the race of his family," Yellin said.

"It's a very meaningful story point for us, that 'The Cosby Show' kind of reconsidered the role that a dad should have in a family, in a very serious and important way, with great comedy, great writing, great acting."

"I would have loved to have had him, but we got [producers] Marcy Carsey and Tom Werner and we had [former NBC entertainment president] Warren Littlefield, who was great on that, so we'll see. But we're very happy with it."

Cosby wasn't the only big fish Yellin couldn't land. James Gandolfini ("The Sopranos" doesn't do this sort of thing, either, he said.

And "we didn't have [Jerry] Seinfeld. . . Ultimately, we were focusing on the Larry David character," the one played by Jason Alexander, and David's on the show. "He was great. He's terrific."

But "he only did it because three other people called him up and said, it's OK, this is OK for you to do. He was not going to do it."

Yellin, by the way, doesn't want viewers thinking of the four-hour "America in Primetime," which will air on four consecutive Sundays beginning Oct. 30, as a history of television. It's more an examination of certain types of characters who've recurred on television over the decades, with Cosby's show fitting under "Man of the House."

History or not, is there anyone who was even less available than Cosby -- because they're no longer with us -- whom he'd have liked to have had contribute?

"I would have loved to have had Jackie Gleason," he said. "Because when you look at shows that changed the game," that's Gleason.

And, of course, "I would have loved to have had Lucy."