How about just turning the Peace sign upside down so it represents life and protection instead of death and disconnection to the divine?
It so closely resembles the rune Algiz... and reversed (as it is plastered all over everyone's cars and t-shirts) it just reinforces vulnerability.
http://www.mystic-mouse.co.uk/Runes/Algiz.htm
We all remember Runes on a visceral level because they are in the collective conscious, so having a bunch of people marching against war carrying signs which relay the message of vulnerability is like ice skating up hill.
LOVELOVELOVE,
C
p/s - You ROCK, Cookie!