FVWM2 uses only 1.5MB RAM?!?!? Going to have to check this out. Fluxbox uses ~3.0MB RAM!
How about posting a screenshot of your fvwm desktop on your website to show off your fvwm2rc config?
I can top that: dwm
uses less than 1.1MB of memory. It is an elitist window manager, hence it's lack of popularity. ^^
You can read about it here
Some info from the author:
* dwm is only a single binary, it's source code is intended to never exceed 2000 SLOC.
* dwm is customized through editing its source code, that makes it extremely fast and secure - it does not process any input data which hasn't been known at compile time, except window title names and status text read from standard input. You don't have to learn Lua/sh/ruby or some weird configuration file format (like X resource files), beside C to customize it for your needs, you only have to learn C (at least editing header files).
* Because dwm is customized through editing its source code, it's pointless to make binary packages of it. This keeps its userbase small and elitist. No novices asking stupid questions.
I've been playing around with it since version 0.1 - I have compiled it on OpenBSD 3.9, pdaXrom, Gentoo Linux, Fedora Core... long as you have a good amount of X11 headers installed, it should compile OK.
Keep in mind, the author wrote dwm for himself. wmii
is another project of his that has plenty more features with an active community.