U can use the extract feature to save and reuse custom objects.
Adding custom items to the library has been suggested before and I think Lars and team have this on their list.
Sharing objects with other users is a great idea.
At
http://capture.highvoltagedesigns.se I'm sharing my custom object with the world.
I'm hoping that capture will make their own sharing-site for all users.
I second the suggestion for a favorites folder, great idea!