If you're interested in "alternative" SFF systems then you may want to check out Soldam's barebones units. They're more expensive than your typical SFF system but they're built with the best materials and of extremely high quality.
http://www.9-muses.com/freak/reviews_comments.php?id=P70_0_2_0
http://www.9-muses.com/freak/reviews_comments.php?id=P70_0_2_0