This is not so much a feature request as perhaps it is a hidden, little known, freely available feature.
Having used sxhkd in fvwm3, I have to say it is both highly functional and allows me to readily share the bulk of my keybindings across numerous window managers. I offer this thought more as a suggestion to others who wish to run fvwm along with other wms. As a fan of sxkd, I have to say it is much easier to manage/use most keybindings via sxhkdrc rather than uniquely define them in a single wm each time.