In reply to Dave.

Can't you just use `$wpdb` and it's database manipulation classes to insert, replace, or otherwise manipulate data in a custom table and display them with WP aided PHP?

Seems like the functionality is already there really, and if you want a simpler way, the middle-of-the-road approach of custom post types (really a misnomer for custom data types) with custom fields and attributes is a decent alternative.