Technically, Titanium is not classic, it is just a bit more classic than the newer compatible clients. There is currently (and probably never will be) no way to use a classic client with EQEmu.
If you want to restrict a client's features and access, you can set the expansions field in the variables table to 0 as mentioned in the wiki here:
http://www.eqemulator.net/wiki/wikka...les#Expansions
That will disable races/classes and some other features that are not available in classic. Though, there are some features that I don't think can be disabled quite as easily if you really want to fully emulate a classic client.