Rewinding a pull start is really annoying, but not impossible by any means. Takzilla, I know for sure that Associated sells pull start cord by sections ( I have a spare roll) and there have to be other manufacturers out there with some extra cord.
Hmm, can't find the .21-.28 cord:
http://www3.towerhobbies.com/cgi-bin...?&I=LXUP93&P=0
Found the one I have:
http://cgi.ebay.com/Associated-Repla...3286.m20.l1116
Maybe this would work... its much cheaper:
http://cgi.ebay.com/E-Flite-Nylon-St...3286.m20.l1116