Data Warehouse Physical Architecture Options

Custom Data Warehouse Architecture
Scale not defined
Custom design
  
Fast Track Reference Architecture
Scale between 4 and 80TB
Rapid Deployment and Use reference configurations optimized for data warehousing.
http://www.microsoft.com/sqlserver/en/us/solutions-technologies/data-warehousing/fast-track.aspx

HP Business Data Warehouse Appliance
Optimised for up to 5TB
Highly tuned solution that integrates hardware and software.
http://www.microsoft.com/sqlserver/en/us/solutions-technologies/appliances/hp-bdw.aspx

Parallel Data Warehouse
Scale to 100s of terabytes
Parallel processing (MPP) architecture to gain scalable performance, flexibility, and hardware choices with the most comprehensive data warehouse solution available.
http://www.microsoft.com/sqlserver/en/us/solutions-technologies/data-warehousing/pdw.aspx