Team Foundation Service should begin to work with Lab Management starting with the Visual Studio 2013 release of the Test Controller and Test Agent if you host them in Windows Azure IaaS machines. You'll be able to use those Azure IaaS virtual machines as "standard environments" but not as "SCVMM environments" since they are not in SCVMM. Lab Management currently does not support SCVMM managing Azure-based environments.
This is certainly an interesting area for the product team as we help teams take advantage of the cloud for development & test workloads.
As far as hosted builds, have you looked at the Cloud Build Service that is provided with Team Foundation Service?
Hope that helps!