Ok, I wrote a script for only killing the process (using lxpanel rather than tint2, but I'm sure it should work as well). Then I added in two commands instead of only one.
<item label="Start Echinus Window Manager">
<command>sh ~/scripts/killit.sh lxpanel</command>
The first <action> runs the command sh with arguments "~/scripts/killit.sh" and "lxpanel", which will kill lxpanel.
The second <action> then exits openbox and restarts into echinus.
Here's the script I wrote. (Again, I'm no expert with kill and ps, so be sure to read and understand the man pages before attempting this.
If anyone who is experienced with running ps and kill in this way and happens to be reading this, please chime in with some helpful hints).
if [ "$1" = "" ]
echo "Can not do\n"
PROCESS=$(ps -C $1 -o pid=)
if [ "$PROCESS" = "" ]
echo "No process $1."
Also, it may be more prudent "not" to leave this so ambiguous. Instead have the script kill tint2 explicitly.
kill $(ps -C tint2 -o pid=)
This way it kills only tint2, and there can be no accidents with running the script with something else.