There are a few of them depending on your requirement and which country u want to colo in.
Net263, Cendata in China
iLink, iAdvantage, Hutchison GlobalCenter in Hong Kong
I am more familiar with HK and China than the rest of Asia, I colo a few servers in HK and found the speed to be great
HK is a great place to host/colo since it's geo distance to China is fairly short and it has awesome ping times to anywhere in the world and the rest of Asia. I want to colo in China but I don't think I can trust them.
PM or post more info. so I can offer u more advices...