In order to have a clearer view and begin fiddling with this, I took the code in adrian's sandbox (currently raw php), and wrapped it in a fapi3_test module, which provides some test pages and a bridge with the current implementations of drupal_render and form_* processing functions - so that generated forms get in the form submitting / validating workflow. I think this could be helpful to anyone willing to work on the area (Darrel, I don't know if you started something, but this should not really interfere) I'm not really sure of the best way to make this available, though. I don't think this list accepts attached files, and committing this to my own sandbow would be sort of weird, since it's 95% adrian's code. For now I posted it in the "CCK in core" thread Karen opened in the CCK issue queue : http://drupal.org/node/115822 (even though the FAPI3 road for 'fields in core' largely exceeds CCK-as-we-currently-know-it, so it might be better placed in core issue queue ?) yched