Mark, like MRUSA, I thought there was some ambiguity in your post as you made a point in stating "First, Monaco is IN business" and wanted to clarify they may have the name, but not the coach -- at least in a way that the OP, myself, MRUSA, and, it seems, you, would consider it. I apologize for my part in misconstruing where you were coming from.
And in a nod to tyoungs let me add that while I am a BIG fan of the Roadmaster S-Series chassis, I would much rather have a Cummins engine in it than a Navistar (yes, I know some of the models I list below often had Cats (Beaver) or DD S60). So I should have been clear I was talking about the "old regime" rather than just focusing on the chassis.
Regardless, my $0.02 says I would not turn my nose up at a '06, '07, or '08, Navigator, Thunder, Marquis, Signature, Executive, or Dynasty (though I think the ISL is a little under powered for a heavy Dynasty, especially out west). I think these coaches are fantastic -- especially for people who like to drive them as much or more than camping in them.