I would like to share my UX with you.
Thanks! Just what I needed!
Could you share your filter-builder source?
the code is at http://code.google.com/p/filterbuilder-gxt/
If you download the project you will see the examples in it.
This stuff is really great!
Funnily at first look I was thinking that it is some ugly crap, but after trying it had to realize that it is an awesome stuff!
Lesson for me: Don't judge by first look!