XboxAuthTool is a C# console application that allows for the generation of specific XboxLive auth tokens from a console's device token.
xboxauthtool.exe devicetoken/pathtodevicetoken sandboxID relyingparties
http://attestation.xboxlive.com, http://xboxlive.com, http://xkms.xboxlive.com, http://vortex.microsoft.com, http://update.xboxlive.com and http://login.live.com