I do apologize for not explaining myself more clearly. I've focused on data typing, primarily because those are the types of objects I've been working with recently. However, the goal is this:
I have Foo and Bar and Bar inherits from Foo. Since Foo inherits from BaseClass, then all the standard C++/Java OO stuff happens. For instance, if I have the following:

package Foo;
use BaseClass;
@ISA=qw(BaseClass);
Foo->define_attributes(
    attrib1 => 'NUM',
);

package Bar;
use Foo;
@ISA=qw(Foo);
Bar->define_attributes(
    attrib2 => 'NUM',
);
[download]

Bar would now have two attributes - attrib2 and attrib1. This would be a full implementation of the is-a style hierarchy, something lacking in the native Perl language.

I'm not looking to create a struct ... I know that's out there and probably done much better than I ever could. However, what I am looking to create is something that would give a solid OO foundation to someone who wants to use it, but doesn't want to re-invent the wheel.

I don't know ... something that maybe does private, friends, shared, public, etc. I'm not quite sure on how far to take this, or even if this would be well-received by the Perl community. This would be my first modules, so I wanted to start a discussion on PM first, to see what people thought of both the idea in general and my idea in specific.