Valery  Pryamikov has released an update version of his RunAsAdmin tool.  This version has a lot of new features including policy and stronger integration with the shell.  This version is still in Beta but it's been very stable for me. 

http://www.harper.no/valery/PermaLink,guid,9dfd759b-6d53-4b97-8db8-350b32d68ab5.aspx