From Cardapio's side of the code, writing a new applet is very straight forward. As you suggest, Cardapio applets are already separated into different files. So all different types of panel applets can coexist in the same codebase.
I think the more problematic side will be the Gnome side (as in, figuring out how to write applets for Gnome3's classic panel).
Not to mention fixing the TODOs that I mentioned before. That may take a while, since it may require rethinking some parts of the Cardapio code design. We'll see...
From Cardapio's side of the code, writing a new applet is very straight forward. As you suggest, Cardapio applets are already separated into different files. So all different types of panel applets can coexist in the same codebase.
I think the more problematic side will be the Gnome side (as in, figuring out how to write applets for Gnome3's classic panel).
Not to mention fixing the TODOs that I mentioned before. That may take a while, since it may require rethinking some parts of the Cardapio code design. We'll see...