Hi there,
I wouldn't know a way to actually modify existing resources off the
top of my head. A possibly
related use case however involves "slots":
http://www.fanstatic.org/en/latest/api.html#fanstatic.Slot
This allows you to defer filling in a dependency until 'need()' time.
I'm not sure this is exactly what you want though, as you do need to
fill in a slot always, and with js.tinymce I
imagine you'd want to have a default. Perhaps it's a place to start
modifying Fanstatic to cover the use case,
however...
Regards,
Martijn