I would not mind it at all if Sally weren't a soprano anymore. Mrs.Lovett was completely changed (vocally-wise) and if the NINE film happens, the vocals are expected to be completely altered to suit the actors. I think if you have seen SOPHIE'S CHOICE and MUSIC OF THE HEART (the beginning at least), you can see how some of us think Streep could make a great Sally.
Laura Linney obviously doesn't have the soprano of a Vicki Clark or a Dorothy COllins. So what? This is a completely different animal. She would be thrilling to watch.
Jewishboy, the reason I think Krakowski would work as Carlotta (and this is of course with the movie going into production sometime in late '08/'09), is precisely because she is older and looks younger. Carlotta is not a washed-out old lady like the productions with Ann Miller and Donna McKechnie in the role make it seem. She was a chorus girl just like Phyllis and Sally, she was the girl having affairs with all the other taken guys, she is living with a 27 year-old. I can totally see Krakowski in the role, of course if she were made-up and costumed to look a certain way. In 30 ROCK they have managed the nearly-impossible task to make Krakowski incredibly un-sexy and grotesque, so she has it in her.
If they go for people like Linney and Marissa Tomei or Vanessa Williams, Krakowski would fit right in. If they go more towards Glenn Close, Meryl Streep, et al, then she wouldn't make much sense.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"