For new Perl OO work, use a well developed and well exercised Perl OO framework, rather than repeatedly coding OO bits and bobs from scratch. I'm leaning towards recommending MOOSE and DBIx::Class (if that's even possible given what we have).

FWIW, Moose is also built to work well with existing CPAN modules and non-Moose OOP, the MooseX::NonMoose extension makes it pretty much painless. It works best with HASH based objects of course, but other people have had success subclassing GLOB based objects (see MooseX::GlobRef::Object and it's SYNOPSIS which shows it subclassing an IO::File object). Beyond that you can use the "handles" option in Moose to do delegation to any other type of Perl object. One caveat is that handles => REGEXPR will not work with objects that use AUTOLOAD because it cannot determine the method list to filter with the regexpr, but this can be worked around by simply specifying the full method list yourself.