A simple alternative would be to have an option for logging messages to a file (presumably something like
messages.txt in the profile directory, which is by default truncated each time conkeror starts), and then
have a command like M-x messages that invokes an external program, like tail -f   or emacs in an
appropriate mode, to view the messages file.  Aside from the "(ab)use Conkeror as a window manager"
reason, I don't see any advantage in having it built into Conkeror.  If this seems acceptable, I'll go
ahead an implement it.  (It isn't very difficult, after all.)