When we were running Miniand it was one of our big goals to assist hardware startups interact with factories in south China; we lived in Guangzhou back then and had constant interaction with manufacturers. We successfully manufactured our own dev board (based on an existing board with modifications) but in the end we just didn't make enough money to make it viable for us.

Chinese manufacturers do tend to have room to move on samples and MOQs, I think it's really important for someone considering attempting hardware on the smaller scale have someone in China assist with interacting with the manufacturers. A big issue is the large amount of miscommunication which always seem to happen when western companies try to deal with manufacturers directly.