Bass pedals only in China / Japan?

Honestly not really. With the advent of ebay and forums that ship sailed a long time ago.

 

If you were going to Tokyo, there are many guitar shops located around Meiji University (you can google it, search "guitar store" around Meiji University), there is a Japanese Brand called Bananana, some stores have those freak pedals right in front of the store showcase

BANANANA effects

 

in Beijing, you can find Red Music Works:

RedMusicWorks

Location info:
Contact us|RedMusicWorks

You also can find Guitar Cube (A high end gear Distributor over China in Beijing, they got a big Chinese pedal brand - Hotone, maybe they got something you need):

代理品牌 - 北京魔方乐器

 

Paging @Feral Feline