Loading assets bundles & accessing of RT Classes

The basic idea is this: I want to create visual assets in the Flash IDE. All assets will have class linkages. All classes will either have a base class of MovieClip, Sprite or BitmapData. All assest have a manifest XML file that goes with the asset bundle.

When the main application loads, it loads the assets bundles (both the SWF and the XML). The purpose of this is to be able to use the classes at runtime. Does anyone have any suggestions for implementing this? I have a good idea as to how to do it, but would like some input. Also, I tried looking for an existing Asset manager type class with little luck.

Thanks