Hallo!
You could built your own bp2~ using elementary filters.
yeah, i personally would prefer that way, but i know too little about filterdesign to implement it myself.
I think it is not a good idea to represent every object in abstractions ... why not is the c object if it is already here and wide distributed (like the iemlib). I know that its nice if there are no additional dependencies, but then you restrict yourself to a given set of object, where one person decides if you can use it or not (Miller) - and not everything is possible as abstractions (at least not efficient).
LG Georg