Actually the new flag should be a patchwork so that repairs to it are not obvious, with the current designs being prodomonately one colour none are suitable.
http://www.stuff.co.nz/national/politics/65798933/...
this is by far the most economic and pragmatic appraoch, it could be a patchwork of all 40 shortlisted flags so that no one feels left out. Every flag designer gets a participation award.