Thanks for sharing that great article, Seed, it is a thoughtful and balanced look at the many aspects of scape and buds that impact garden performance. For us, we have so little yard left (more flowerbeds than yard now) that just the thought of having rapid increase makes my back hurt. Dividing hasn't been hard for me yet, at the 5-fans or under size, but I would have a hard time digging up large clumps in all the garden areas every three years. I'm so jealous of the larger yards, though, even if I think rapid growth is a gardening task for younger bodies.
I did compile a list of highest bud count here. They include those probably mentioned before that, like Julie notes as being good performers, have just 15+ buds, but that blossom for a long time. In my blast garden, three weeks is a long time ... and successive waves of 105-degree heat starting on June 8 pretty quickly put a halt to all blossoming. The three listed here were in full-sun garden conditions.
Nagasaki, Janice Brown, and Frankly Scarlet each had 16+ buds blossom.
Nagasaki bloomed from May 24 to June 19, Janice Brown from June 13 to July 9, and Frankly Scarlet from May 19 to June 11.