Added the following tags:
<reputation>
<zone>
<lastseen>
Adding the above two items does incur a small cost though during initially starting XBF. In order to capture that information before it is sent through the notification system, the information has to be retrieved. All this means is that the sign-in process will take longer than if you don't use the tags. Yes, this also means that if you don't use these tags, your sign-in time won't suffer because of the addition of these items. I may look into another way to handle this in the future; but for now it's available and we'll see how things work out.
The <lastseen> tag does not add any additional sign-in delay.
As for the request regarding League/Clan names, this isn't something that is available via Live. However, it's pretty simple to add manually (so to speak). Whenever you have your members activate HTTP Notifications, just have them add another value to the template url that contains the information you are wanting. This isn't limited to just League/Clan names. You could have them add real name, what part of the world they live in, etc. An example would be:
http://someserver.com/somepage.aspx?gamertag=<gamertag>&clan=We+Be+Whatever&lastseen=<lastseen>
Let me know if you have any questions regarding this.