BobsUI is a data-entry UI widget set for Morphic which contains a Rolodex example. (It does not include a "GUI builder"... you must specify the widget layout in the source code.) It does support tabbing between entry fields, and a few other niceties. See also GUI Building Tools and Customizing the Squeak UI.
Original version written by Bob Arning, later versions by Doug Way, Doug Rollwitz, and Javier Diaz-Reinoso.
Downloads
The latest version (3.8) is available at SqueakSource... http://www.squeaksource.com , see the BobsUI and BobsUIDevelopment projects.
An earlier 3.x version is available on SqueakMap, and is also available here: bobsUI3a.cs.gz, maintained by Doug Rollwitz.
At some point, UIComponentMorph and its subclasses could be moved out from under AlignmentMorph, since most (all?) of AlignmentMorph's functionality is available in all Morphs now.
Another nice thing would be to improve tabbing between fields so that it includes not just entry fields, but also buttons, menus, lists, etc.
A single-line entry field with horizontal scrolling (without a scrollbar) would be a very nice thing to have. (An entry field which behaved similarly to the URL entry field of a typical internet browser, for example.)