gladepyc generates a Python module from a Glade XML GUI description which builds the corresponding GTK+ interface by using the _gtk module of the PyGTK binding. The building module which is output can be used to build as many separate window/widget instances of the same class as you want at run-time, because each window is translated into a UI building class. It can also, on request, generate UI building code for just a subtree of the UI description.
Gorm (Graphic Object Relationship Modeller) is a GNUstep application for building user interfaces and application objects relationships. Its major features include drag-and-drop creation of GUI elements from palettes, run-time loading of additional palettes, direct on-screen manipulation of GUI elements, manipulation and examination of objects via inspectors, and creation of connections between objects using mouse. It is a clone of the former NeXTstep (currently OS X) "Interface Builder" application.
The Inter-Language Unification system (ILU) is a multi-language object interface system. The object interfaces provided by ILU hide implementation distinctions between different languages, between different address spaces, and between operating system types. ILU can be used to build multi-lingual object-oriented libraries ("class libraries") with well-specified language-independent interfaces. It can also be used to implement distributed systems. It can also be used to define and document interfaces between the modules of non-distributed programs.
Minotaur is a generalized extension which lets you run Python scripts from Tcl, or Tcl from Perl, or any of the other combinations. Minotaur works by loading the appropriate shared library into another script language's context. So, for example, running Tcl from Python means that the Python main program imports the Minotaur extension, which in turn loads the Tcl libraries - thus Tcl becomes "embedded" into the Python runtime environment (which is similar to embedding Tcl in a normal C program). As involved as that sounds, performance is already surprisingly good, and the capability is turning out to be quite useful. Minotaur 0.1 is an alpha level release, meaning: it works, aside from a few quirks and bugs, but its API and implementation might still change in incompatible ways in future releases.