Great looking artisans, Bambino! When the Keybutos are available, I will pick one up for sure. Also, if there's any possibility for Topre in the future, I'd be in on that too.
In terms of input, imo the Keybuto would look nice with the four side edges of the cap being sharper corners. Also, I think a black/red cap would look nice in this design. Although I'll admit I am quite ignorant to Japanese history, wasn't it divided into different provinces before being Japan as a whole? If so, a neat idea for a sale might be to have colours/names for each of the caps corresponding to a province.
Keep up the great work!