The GWM (Generic Window Manager) is an extensible Window Manager for the X
Window System Version 11. It is based upon a WOOL (Window Object Oriented
Langage) kernel, which is an interpreted dialect of Lisp with specific window
management primitives. The user builds a window manager by writing WOOL files
to describe objects on the screen, including a Finite State Machine triggering
WOOL actions on response to X events (e.g. mouse buttons) on that object. These
objects can be used as decorations around X applications windows, as pop-up
menus or as independent windows. GWM should be able to emulate efficiently
other window managers, and play the same role for window managers as EMACS does
for text editors.

GWM comes with already defined profiles (standard, vtwm-like, twm-like,
mwm-like). Some screenshots are avialable on the W3 page. Or you can design
exactly what you want.

WWW: http://koala.ilog.fr/gwm/