Have you got a source for OS X DHCP being vulnerable? OS X has a copy of bash at /bin/sh so it's pretty vulnerable if you can find a way to remotely set environment variables and call system().
Unless the article was changed, the author only questioned whether they were vulnerable, and did not assert that they were: "One key question is whether Mac OS X and iPhone DHCP service is vulnerable..."
One early analysis [0] seems to indicate that OS X not vulnerable to this sort of DHCP client exploit.
