There is a great topic going on over at the 650b listserve.  Tires, depending on the manufactor, even with the same width might have a different outside diameter (OD).  This could be due to the rim it is on, the amount of rubber tread, thickness and so on.

Here is a list that Longleaf Bicycles started on Google Docs.

Do you have any information to add to this list?  Input on how some of these tires run? Let us know!