[eluser]Colin Williams[/eluser]
I actually have a similar real-world scenario happening now. I'm adding a feature to site through which users can create and manage "bike checks" and share these with other users, embed them in social networking sites, etc.
The main object is a bike. A bike is made up of bike parts and some meta info. Bike parts are made up of bike manufacturers and bike part types. I've got a lot of different objects coming together to make one bike object.
I've settled on breaking it down into several controllers, all nested under bike:
bike
bike/add
bike/edit
bike/delete
bike/view
bike/part/view
bike/part/add
bike/part/edit
bike/part/delete
bike/manufacturer/add
...
bike/part_type/add
...
