You can also do carry out (dinner only) at Kimono's in the Swan (a short walk from the International Gateway at Epcot). Their sushi is very good! I've done carry out there while staying at the Swan and Dolphin - it is expensive but really good. My kids like it.
The rolls in the Land pavillion are like California rolls. They aren't bad, but kind of expensive I thought.
I don't know if Japan changed the little bar area, but we used to go there for sushi. It was upstairs.
Also the counter service in Japan has rolls, just one kind I think.
The counter service ones are premade.