> "customizable tiling window manager" somehow requires the user to learn an unusual programming language and a dozen of inscrutable keyboard shortcuts
You might be interested in the tiling window manager I wrote with Node.js (mixu/nwm on github). It's very much inspired by xmonad and dwm, but the engine is Javascript running in Node.js with a native extension for X11 operations/events.
All layouting decisions are made in JS - in fact, the C++ binding doesn't even know the position of the windows or the dimension of the monitors; it's all tracked in JS. It should be easier to customize, though definitely not as battle-tested as xmonad.