Looking at SQL Server maximum capacity limits on here: http://msdn.microsoft.com/en-us/library/ms143432(v=sql.120).aspx
Database size can be as big as 524,272 terabytes.
Here, you could see VM size limits on Azure: http://msdn.microsoft.com/en-us/library/windowsazure/dn197896.aspx
If you look at the table on the second page, the maximum number of data disks that could be attached is 16 (1 TB each). Does that mean on Azure, SQL Server cannot house more than 16 TBs and anything more than that would require a new VM?