Hi,
The best doc we have found so far is one I'm sure you have also found in your investigations: "Network Virtualization - Path Isolation Design Guide" at www.cisco.com/application/pdf/en/us/guest/netsol/ns171/c649/ccmigration_09186a0080851cc6.pdf. This doc was written at Cisco in 2007 and does have information about deploying path isolation. I found this doc by doing a google search on "path isolation" and got other hits as well.
Many design guides or white papers are not published externally because they are written for specific customers and scenarios. You might want to contact your Cisco Support representative to see if there are any such documents that would help you.
I'd also recommend posting an inquiry on the more technical support side of NetPro at http://forum.cisco.com/eforum/servlet/NetProf?page=main
thanks,
Linda