Here's an idea. WHy not write your own format in XML, do all your management in XML, and use XSLT to write bind format files. That way if the BIND people decide, "wait, let's use format X", you have less to worry about. Just rewrite the XSLT and you won't have to change your programming.
well.. just that inside the xslt, but that's easy enough :) At least you won't have to write another script to go from bind 9.x -> bind 9+n.x