When the create database statement is running, it requires exclusive access to model database. Now that you have killed the sessions, do you see any other session blocking it?
select * from sys.dm_exec_requests where blocking_session_id<>0
If that query is not causing any performance issues, you can wait for it to complete. Restarting the SQL Server is also an option but I don't think it will cause the MODEL database to go suspect.
Pradeep Adiga
Blog: sqldbadiaries.com
Twitter: @pradeepadiga