I assume you have found the xml file to modify for the datacenter location, and how to tag the compute resources with the associated datacenter label? Problem here is that I don't believe you can make location a required field, I tried in previous versions to define the customer property for the location and make it required in a build profile, but it didn't override the location field as I had hoped.
If you are using vCenter for your endpoint, do you have multiple vCenters or a single vCenter managing multiple sites? The idea is to distribute the DEM's and Proxy Agents close to the endpoint they interact with. If you have multiple vCenters and you deploy a proxy agent in the same site as each vCenter, using the endpoint configured for that site's vCenter server. If you have a single vCenter server, you don't need to distribute the proxy agents to the sites, as it only talks to vCenter, not the ESXi hosts.
If we are talking DEM's (Amazon EC2, Physical, Custom workflows, vCD - I think), you can deploy those close to the end points and try and use Skills to associate a skill for that particular location if you are able to make a relationship. I don't believe there is currently a way to associate a DEM with a location.
Challenge I have run into, is your blueprint has a name of a template and you want to use a site local template. I got around this by having a powershell script run at submission time that looked up the location and added a suffix to the CloneFrom custom property that had a site code of 3 letters, and named the templates at each site accordingly.
Probably hard to follow above, but if you provide more details on what you are trying to accomplish, might be able to help more specifically.