One of the key concepts behind Redfoot and, more recently, the TrIM project I'm working on with my sister, Jenni, is the notion that with a rich enough object schema, UI can be provided by the framework and objects can be manipulated and relationships express via that generic UI.
Via the session schedule for the Boston No Fluff Just Stuff conference, I found out about Naked Objects.
The session description reads:
"What if you never had to write a user interface again? What if you could simply expose your business objects directly to the end user? How would this affect your productivity? The way you work? The flexibility of your applications? Is this even possible? Sometimes, yes. This talk describes a style of application development, Naked Objects, where you write just the business objects, and a framework lets your users interact directly with these objects."
I tracked down the Naked Objects website and it turns out there is a book, which definitely looks worth getting.
A quick perusal suggests that the approach (at least as it is implemented) relies on classes written in some specific OO language rather than something like RDF. I think I'd prefer the flexibility and interoperability that declarative object schemas would provide and there's no reason why the Naked Object approach couldn't use RDF (or perhaps XMI?) with logic written in something like Python.