All of these support data-entry Forms to one degree or another; some support Cloning (Logical-Linking of nodes), a crucial feature for any relational implementation.
Treepad
http://www.treepad.com/
Treeline
http://www.bellz.org/treeline/
Smart Outline
http://www.smartoutline.com/default.asp
The Literary Machine
http://www.sommestad.com/lm__index2.htm
Brilliant Database
http://www.brilliantdatabase.com/index.html
There may be other programs that offer Forms support.
I was surprized to learn that UR does NOT support Forms, but my surprize was due to my misunderstanding of the feature set presented.
Seems to me that it would be nice to have the ability to do both free-form and structured data within an outline presentation; the authors of UR have shown with the Contact Template that Forms can be done....
Later,
KenA