IIRC you can still set the index, it's just that you can't do matching if the match/content is over the length and it can still do begins with matching.
That said, I still don't get why they didn't just change the behavior for TEXT/NTEXT vs adding (MAX) options.
edit: I am mistaken, when setting an index, the index max is now the insert limit (from response below).
If your referring to SQL Server you get on insert "Operation failed. The index entry of length 901 bytes for the index 'xyz' exceeds the maximum length of 900 bytes."
That said, I still don't get why they didn't just change the behavior for TEXT/NTEXT vs adding (MAX) options.
edit: I am mistaken, when setting an index, the index max is now the insert limit (from response below).