After having spent some time on GWT + Databinding I can now report success on porting over the Core-Databinding framework to GWT with fairly no changes from what is found in the Eclipse-CVS-Repository.
But to do real programming in GWT there's more you need (Views, Editors, Commands, Actions, ...) so I've also taken over the other core ideas from Eclipse into a GWT-Lib I called gjface (it isn't a straight port of the Eclipse-API currently because of the lack of time but it's fairly usebable already).
I've also created a Demo-Application you can find here and if you are interested how this Application is created you can get the source from here. I have only tested it on Firefox so it might be that it's not working on IE currently.
I'll blog later today how this all works together but if you want to take an in depth look I'm at ESE!