In Taiwan there is a variation of 飯糰/rice balls shaped like a triangle but no seaweed wrapping, usually with 肉鬆 (pork floss) in the middle, which have been around forever as a breakfast item. The Japanese type wrapped in seaweed with better ingredients started popping up in 7-elevens about 15 or 20 years ago, and are known as 日式飯糰 ("Japanese food rice balls"). I think they cost about NT$40-50, or around US$1.50. It's not enough for a meal, but as a snack they're great.
飯糰 also come in a Shanghainese variety (粢飯）. They're long and stuffed with a deep fried dough stick 油條, the pork floss, and sugar. As well as a savory variety with mustard greens 榨菜. Seems like the Taiwanese version is fusion of both Chinese and Japanese styles for Taiwanese tastes.
McDonald's had nice rice bun burgers in Asia. Apparently originated in Japan (MOS chain), and also popular in Korea. I'm still waiting for this variation to make it's way to the west.
