Reread my previous post.
Then readup on Components and Dynamic Components (which are actually Components with special Attribute Dictionaries.)
What you really need to do is create a Building Component Manager plugin. But the buildings themselves will have to be Components, and/or Dynamic Components (which will likely have a "Building" Attribute Dictionary attached to them, with keys and values that your manager will use to keep track of and organize them.)
Now.. it IS possible that within your manager namespace, you can have a class Building, whose instances hold a reference (instance variable,) to a Component Instance that is actually in the model.
The SKP file format has an embedded thumbnail image, which if you have that file in a link in the browser (I'm talking webdialog,) then the thumbnail should display just as if you had any other image filetype on a webpage. It may be possible to drag and drop from the webdialog into the Sketchup client area. (We know we can do this from a folder explorer window.)
Do a search for other topics on "Warehouse" as others have discussed making a webdialog or website similar to Google's 3DWarehouse. You may pick up some ideas in those threads.
