There's a new small one in the GCs just now 'Kojo-no-mai' suitable for a large pot. It grows eventually to about 6feet, I believe.

Please tell that to the one in my garden. It is 6 feet tall now and it has been cut to the ground twice.
There are some very nice dwarf Prunus around, you just need to go searching for them. However even the smallest ones would eventually outgrow anything but the largest container. They all have quite far spreading roots.
Having said that some of the Bonsai Cherry trees are tiny, floriferous and beautiful.