I have thought about an OpenACS IDE as well. The Brazilian "Miolo" project (a PHP implementation of something like acs-kernel) developed one called "mioloide" (which sounds funny in Portuguese):
http://mioloide.codigolivre.org.br/Those guys are so PHP-centric that they go through the pain of developing in PHP-gtk.
An IDE that would hook up to your database to identify tables, help with queries, help create a skeleton of a package, help generated ad_form statements (including validate blocks), would be very helpful.
-Roberto
