Kde used to offer a way to run an app in the backround root window, at least in version 3.
The only way to run root-tail in gnome is to shut off nautilus.
Most window managers/environments these days run a window on top of the root window for use as a desktop.
I used to have 3 or 4 log files tailed to the root window in enlightenment and gnome 1.
I dont think fluxbox draws a root window either.