This is cool :) I've actually created something similar for a work-related project, but it's specifically based off Core Data entities and uses QuickDialog for creating and managing the elements (so supporting all the Core Data attribute types is easy, and you get the benefit of the QuickDialog style provider/skinning support). For customisation and validation I use Core Data's user info on properties, which means it's easy to create fully-fledged forms with all attribute types and entity relationship types, predicates, and lots of other little things I've needed with basically zero coding.<p>It's kind of turned into a DSL specified within the Core Data model editor, but with the nature of the project it was for it's saved me a lot of time. I'd love to open-source it if there was interest, but I'd have to look into the logistics :)