Title isn’t enough to get across the idea that I would love to see a movie with a dozen or more “second level” actor/star types that would rival those Poseidon Adventure or Cassandra Crossing things of the past.
The main idea is the cast. We can decide the plot and that sort of thing later.
Add to this list of “stars.”
Philip Seymour Hoffman
David Strathairn
John C. Reilly
Delroy Lindo
Laura Linney
Felicity Huffman
Hope Davis
Patricia Clarkson
From your list, I take your definition of second-tier to be in reference to movie star status and not talent. When that’s the case in these sort of hypotheticals, I can always safely scalp actors from HBO’s fine original programming. I’ll artificially limit myself to three from each show - with apologies to actors I pass on.
Deadwood:
Timothy Olyphant
Ian McShane
Garret Dillahunt
Rome:
Kevin McKidd
James Purefoy
Kerry Condon
Six Feet Under:
Frances Conroy
Michael C. Hall
James Cromwell
Generation Kill:
Alexander Skarsgård
Michael Kelly
Lee Tergesen
Band of Brothers:
Neal McDonough
Ron Livingston
Donnie Wahlberg
Something the Lord Made (movie):
Mos Def
Alan Rickman
Gabrielle Union
Had to stop somewhere!
You have definitely picked up on the vibe I’m after, drastic_quench 
Good sources, too. Showtime’s shows are also a good source in some cases.
Another concept to re-cast, at least in the headliners section, would be the Ocean’s X-Number after Clooney, Damon, Garcia, Roberts, Pitt, and a few others have been rejected for being “too pretty” for the movie.
So if we follow the Towering Inferno template, we need some people who can do rich and glamorous, because it will be some fancy dinner going on when disaster strikes.
We need the following:
A couple of rugged action men (Steve McQueen, Paul Newman, though this is 2010 so one of them could be a woman)
Sports star (O.J. Simpson)
Female singer in a cameo (Maureen McGovern)
Handsome, distinguished middle aged man (Robert Wagner)
Imperiled children - preferably a boy and a girl (Mike Lookinland and some girl)
Aging Hollywood legend couple (Fred Astaire and Faye Dunaway if memory serves)
I don’t remember the movie that well but I think we need the arrogant business man who cut corners on safety because he was sure nothing could go wrong but ends up cowering in fear. Maybe this would be a good role for Phillip Seymour Hoffman.
Maybe Celine Dion for the singer?
Maybe The Rock for the Sports Star?
I would love to see any movie with all those people. I especially want to see a film with Linney, Davis and Clarkson playing sisters. Oh when will someone make that happen?!
Seems to me Billy Zane should be in there somewhere.
Oh, and John Lithgow.