Jacques,
Welcome back!
That is a pretty extensive list you gave us. But that was a pretty extensive list too. It should keep you researching for months.
I think there are a few that will meet every one of your criteria. My personal choice would be a Howeara Lava Burst cultivator. They are small in all their directions, bloom constantly and are perfectly content in a window sill garden. The flowers are small individually but there is never just one.
Daisy
