Did this back in 2004-2005. Web framework prior to even knowing about then evolving web tech in Java, Ruby, PHP,.Net or any others.. Down the last two years realize how far the work I had done, had the concepts of XML configurations/ Ruby on Rails like folder/code generation etc all these platforms have evolved on. Deep regrets, I did not dive in deeper, work smarter, push this into the world of open source then itself, limited as I was then by Visualworks licensing. In Smalltalk, seaside unfortunately never has made it mainstream it deserved to be.
Plugin a workflow / Rules engine it could be different tool altogether. Modify the complexity of external XML configs to more code oriented debuggable configs. Work around the limitation if any of depending on smalltalk ssps, re-engineering the original concept that was contemporary to Ruby RoR and much before the Groovy Grails.
The need is for a more drag and drop composition with minimal code intervention, yet fully debuggable as a code when required. Least and the essentials in XML configs, a folder structure to obtain flexibility of image, css, js handling.. Ah for the regrets of not sticking on with the drive I had then.. but even now, I still see in web tech gaps in reaching these goals fully. The cheese has not moved dramatically as yet, though RoR and Grails have their niche..