References for usability testing agencies needed (USA, UK, China)

We (a customer experience consultancy in Vienna/Austria) are looking for agencies that can help us test ecommerce designs in the US, UK and in China. We would set up the tasks, but the recruiting as well as the testing itself and the reporting would have to be done by these agencies.

Does anybody here have references for this kind of work?


I do not know this kind of agencies. But if you hire me, I can help you.