There really are quite a few modules now that do this sort of load/modify/save persistent objects stuff, the best known being Class::DBI and Tangram. Most of them show enough code in the synopsis that you should be able to see that they do these same things.

Yours seems to create tables based on a class declaration. Tangram, XML::Comma, and maybe some others do that, but Class::DBI doesn't. It could be an interesting add-on for Class::DBI.

Other than that, I'd say the most significant differences are the HPLOO syntax (neat experiment, but I wouldn't use it on my projects because it isn't really Perl and I would worry about other people understanding my code), and the features that other projects have which this one doesn't (triggers, constraints, ways to remap existing databases to accessors with different names, ways to use direct SQL, relationships between classes, etc.).

There's nothing terribly wrong about your system, but I can't see much reason to recommend it right now when other systems have so much to offer.