Method 1, External

We can kill Conkeror's scrollbars at the system level by making a small GTK2 theme with scrollbars of zero width. We can then run Conkeror with this theme in effect by a small change to the way we launch Conkeror. This method eliminates all scrollbars, including those that would normally be in content frames, iframes, or editing areas.

First, make a file ~/.gtkrc-2.0.conkeror with the following contents:

## uncomment the next line to also load your normal .gtkrc-2.0
#include "/home/YOU/.gtkrc-2.0"

style "noscrollbars" {
  GtkScrollbar::slider-width=0
  GtkScrollbar::trough-border=0
  GtkScrollbar::has-backward-stepper=0
  GtkScrollbar::has-forward-stepper=0
  GtkScrollbar::has-secondary-backward-stepper=0
  GtkScrollbar::has-secondary-forward-stepper=0
}
widget "MozillaGtkWidget.*" style "noscrollbars"

Then, launch Conkeror like this:

GTK2_RC_FILES=~/.gtkrc-2.0.conkeror conkeror

Note, if you don't use any other Mozilla-based programs, or don't mind losing scrollbars in all of them, you can put the GTK2 theme snippet above directly in your ~/.gtkrc-2.0, and not bother with the GTK2_RC_FILES environment variable.