We were mentioning TT because it's good and some of template modules was ment to be used with CGI::App (or other MVC frameworks). So obviosly it doesn't help much with authentication. Closest thing would be to display one thing (perhaps menu) to auth. user, and another thing (login form) to non-auth. users.
Anyway TT can be used for generating lot's of pages from one template. But it's more usefull if you use it to separate perl code (Model in Mvc) and html (View in mVc) ...
Have you tried freelancing? Check out
Scriptlance - I work there. For more info about Scriptlance and freelancing in general check out
my home node.