Depending on the version of the SQL Server you are using you could use a DDL Trigger for Logon access. You can have full control on who/what/when/where. You will need SQL Server 2005 (SP2 I believe). Here is a good link about this technique:

http://blogs.technet.com/vipulshah/archive/2007/12/04/ddl-triggers-and-logon-triggers.aspx

Thanks