Are there third party providers of Mechanical Turk psychology experiment services? For various reasons it can be difficult to run a Mechanical Turk experiment (i.e., you don't have the technical expertise, you don't reside in the United States, etc.)

Have any third-party providers arisen with the express purpose of managing the delivery of psychological experiments using Mechanical Turk?

Update: Ideally, I'd like to know not just about how to get around the United States restriction. I'm also interested in services which manage the process and are specifically set up with behavioural science experiments in mind or at least offer a suite of services, one of which is tailored to behaviour science experiments.
I would like to acknowledge the contributors to this post on stackoverflow.
Using Amazon MechanicalTurk if location != US?.

This question was posted a few years ago, but this answer is current.  

Houdini is a third party platform for MTurk, designed for non US users.

This question also leads to Houdini enabling non-US based businesses accessing mTurk.

At this stage, I have not found other providers, let me know if you'd like me to investigate further.

I have provided a link of crowdsourcing services similar to mTurk.