In case you haven't seen it, I developed a list of tools which is available via Mosaic:
At the end of my list are some references to other UI Software Tool information.
On Unix the most interesting is probably Garnet from CMU. It is free and uses Common Lisp and a small, fast constraint system. There are GUI tools that allow a high degree of programming by example. Performance is notably good when used with high quality CL compilers, e.g. Franz and Lucid and CMU's own.
There is a port underway, I think, at CMU, to get Garnet running on Macintosh Common Lisp.
On the PC, there is Franz's Allegro Common Lisp which has a high level GUI system and a GUI builder.
There is also CLIM, the Common Lisp Interface Manager. This is also notable for its high level capabilities. It is derived from the Symbolics Genera GUI, which was ahead of its time with its use of "presentation objects" and application framework. Commercial implementations of CLIM are available for Unix CL's as well as Macintosh CL (I think). I think Franz is working toward a CLIM for ACL/PC for Windows.
There is an X-based, free implementation of a Genera/CLIM-like GUI, but I do not believe it is being actively supported anymore.
For more information on any of these, I'd look for the Lisp FAQ and then post questions to Comp.lang.lisp.
At one time devGuide (SunOS) could produce LISP code with appropriate LispView calls. I haven't used it in several years, though, so I couldn't tell you if this is still available.