For Mr. Mike
I bought the 4/0 blades from a tool company called Gesswein (gesswein.com). They are a company that makes tools for the dental and jewelery trade. They have a catalog online and the scroll saw blades are listed. They have them available up to 9/0. I have used the 9/0 on some VERY small cut outs and when cutting veneer. The 4/0 blades are $24 for a gross.
Hope this helps,
Mike