Latest CRM 4.0 rollup 10 released on 3/June/2010.
Rollup 11 can be uninstall on server
Rollup 11 is cumulative.
Rollup 1,2,3,4,5,6,7,8,9,10 are not prerequisites for server portion.
Update Rollup 7 is a prerequisite for Microsoft Dynamics CRM for Microsoft Office Outlook and Microsoft Dynamics CRM Data Migration Manager.