Is there a way with rosrun and/or roslaunch to specify the verbosity
of logging messages on a per-node basis? So say I have a complex
launchfile with many nodes, one of which is acting up, and I want to
see that node's DEBUG messages. I know I can change levels with
rxloggerlevel but it seems that I might be missing messages that occur
between startup of the node and when I change the level with that
tool.

It seems that this can be done by editing
$ROS_ROOT/config/rosconsole.config, but $ROS_ROOT (/opt/ros/unstable
in my case) is not user-writable on a deb-installed system so this
seems like a less than ideal option. Also I assume that if my node is
being started on a remote machine with the machine attribute in
roslaunch, that I would have to change rosconsole.config on that
remote machine, not on the local one, is that correct?

Thanks,
Pat