Virtual directories in ck(eg file hosting websites, Salesfor

I have successfully installed ckFinder - very nice.
Now I'd like to be able to show not just locally stored (on my server) files, but files stored elsewhere, for example on a file hosting service (fileplanet, flickr, salesforce documents).

There are a variety of reasons for wanting to do this (not least of which is they have gobs of storage space and its cheap / free and they have plenty of bandwidth, both of which my little server does not)

I would only require read/only access (eg no upload, rename, delete). Its easy enough to emulate a hierarchical "folder" structure and files within those and to return the appropriate link for a chosen file.

Do you have any recommendations for how to go about doing this ?

I have started by creating another $config['ResourceType'] but ran into FileSystemHandlerBase checkRequest() trying to create directories on my local machine, which seems aggressive
So before I dive too deeply I just wonder whether the developers could comment on whether this is a reasonable experiment or the current architecture makes too many assumptions about having a locally accessible filesystem.

If not, which objects / calls should I focus on modifying or subclassing (preferrably I could just make new subclasses and instantiate those from a factory when user is looking into a virtual file system ResourceType), most likely GetFiles.php, GetFolder.php

Any guidance welcome, if it is not too much work, I am happy to dive in and even contribute the code back to the project, might be useful for other users also.

Thanks
Robert