I suppose I should've said that my list was not complete, nor was it necessarily perfectly accurate.

I forgot to include Urahara, it was late, my mind was working at like 20% capacity. He's definately on the list, and definately ranked with the stronger captains.

Uryu is completely overshadowed by his father, and Yoruichi is definately at least medium-strength captain level.

I will update the list later.