Consolidating multiple database servers into a single server makes it possible for an organization save hardware, software, and operational costs. To help quantify the potential savings of SQL Database consolidation within your organization, Dell has partnered with Principled Technologies to bring you this consolidation whitepaper as they examined an example test case: How many Dell PowerEdge 2650s can you consolidate onto a single PowerEdge R805 with a Dell PowerVault MD1000 storage array attached?
more at http://databasenews24x7.blogspot.com/2009/05/consolidating-sql-2000-to-sql-2008.html