Available here: http://dmitriid.com/files/projects/skins/bbpress-mamut.zip
Used here: http://erlang.dmitriid.com/forum/
It may not look much, but i haven't added any backgrounds or anything. Feel free to adjust it for yourself.
This template is derived from three-column flexible layout available at
http://www.webproducer.at/flexible-layout/
NOTICE. The template assumes you have the following plugins installed:
* bb-ratings.php, http://bbpress.org/plugins/topic/6
* since-last-visit, http://bbpress.org/plugins/topic/30
* online-list, http://bbpress.org/plugins/topic/24
If you don't have those installed, remove corresponding function calls from the template