Windows Azure Virtual Machines now has a pre-built image for BizTalk Server 2013. This will enable you to get up and running with BizTalk 2013 in just a few minutes. Configuration is needed once you create a new virtual machine using this image.
The pre-built Image includes the following:
I was able to create a new virtual machine using this image and configure BizTalk. The Rules Engine failed to configure, but I did not look into why.
Let me know if you run into any issues with the Image.