Hm, don't know if this is what you have in mind, but as far as fine-grained access control goes, you could do away with the need to do something fancy in Perl if you chose the right DBMS (assuming you have a choice).

e.g. MySQL has decent permissions model (you can, for example, let user 'bob' have select and insert privileges when he connects from foo.com and give him all privileges if he connects from localhost.

Just a thought.

Philosophy can be made out of anything. Or less -- Jerry A. Fodor