Hi Arjun,
I don't think its needs to be mounted. I think a good set of tcl API and DB API will be good. Some tcl API is to make make a fragment of the form much like GC. Also it would also be good to bind the content_item to an object_id rather than package_id. For example the one that I made in the ticket tracker lite. For each ticket (an object) I bind many attachments to a ticket. The way I did it was very simple I just pointed cr_items.parent_id to the ticket_id. No more mapping tables.
I have given Vinod the code not sure it it made to the OACS code tree. So I guess that attachment package should make it very easy to bind binary files to objects (e.g. ticket, bboard post, news items, etc.)