I put out the first "release" of my little gxtforms library.
Demo (with source tabs) here:
I was inspired by the django admin when I created this tool. The basic idea with this library is that you would annotate your model classes and the gwt forms can be auto-generated for you.
Please have a look and tell me what you think. Definitely consider notifying me if you plan to use it.
At this point, the license is GPLv3 (the same as the free version of GXT), but I would consider changing the license if someone can convince me that a different one would be better.