I have been a fan of the Data Warehouse Appliance for some time.  The concepts, technologies, and price have real game changer qualities.  Doug Henschen, Editor-in-Chief at Intelligent Enterprise, has done some research on companies who have implemented Data Warehouse Appliances and in his article "Why Not Data Warehouse Appliances?" (http://www.intelligententerprise.com/blog/archives/2008/05/why_not_data_wa.html), Doug also makes the case that "we’re on the cusp of a broad adoption phase".