I have just compared the C:\Windows\PolicyDefinitions folder on the Widows 8 preview build with a Windows 7 Enterprise build. And unless I missed one, the below ADMX/ADML files are new.
AppxPackageManager.admx
dam.admx
DeviceCompat.admx
EAIME.admx
EarlyLaunchAM.admx
EdgeUI.admx
ExternalBoot.admx
msched.admx
ProximityCommon.admx
srm-fci.admx
UserState.admx
WindowsHistoryVault.admx
WinStoreUI.admx
wlansvc.admx
WPN.admx
WPN.Provider.admx
wwansvc.admx
When you open the related ADML files stored under C:\Windows\PolicyDefinitions\en-US you will find some interesting hints about what these new policies are supposed to do. You will find stuff about Windows to Go, the App Store, Profiles and more.