In BDD 2.5 there was included a stiored procedure for naming computer from a prefix + sequence. Here is one for BDD 2007 and MDT 2008/2010
IdentifyComputer for BDD 2007 and MDT 2008/2010
http://www.deployvista.com/Repository/tabid/71/EntryId/34/DMXModule/396/ctl/EntryDetails/mid/396/language/en-US/Default.aspx