I'm not an expert in this stuff, but Maarten Balliauw created a Window Identity Foundation plugin awhile back which showed off claims tokens - it may be a good starting point for you.
His plugin is a bit out of date (it will no longer work with Glimpse 1.0+), but it should be easy to update and package based on the custom tab documentation.
I'm also more than happy to help you out. You can contact me on Twitter.