This forum by and large accepts a large number of different bikes as being C&V. I've haven't seen anyone trying to police the boundaries of the category which is, I think, a good thing.

That said, for a first approximation for what is C&V, you could worse than the guidelines for the Cino Heroica which provides:

"What is a Heroic bike? Your bike must have at least three of the following characteristics to be considered Heroic:

• Steel frame
• A frame made in 1987 or earlier
• Non-indexed shifting
• Old style clip pedals and straps
• Single speed
• Downtube shift levers
• Tubular tires
• Fixed gear"

http://www.cinorider.com/the-bike-you-ride/

I'm a little skeptical of the date cut off as lot of great steel bikes were made in the 90s (including all 3 of my B'stone bikes!). Also mountain bikes can be a bit hard to fit into this category but the older high end mtbs with rigid forks are, I think, C&V droolworthy.