There is an interesting thread from Lynn Olson on DIYAudio about open baffle speakers that discusses his ideas for a new speaker as well as some of the the other designs out there like the Orion. It's a huge thread but has been intersting reading.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100392&perpage=10&highlight=&pagenumber=1
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100392&perpage=10&highlight=&pagenumber=1