I can start by saying Propolice can't be a port because there are too many 
patches to /usr/src. I've taken the patches from ibm, freebsd, and openbsd 
and put these patches together with bootstrap instructions for NetBSD 
-current. My patches and instructions were designed to work on all platforms. 
Everything you need to build NetBSD with default stack protection is here:
http://www.linuxfromscratch.org/~robert/NetBSD/netbsd-ssp.txt

Includes patches for gcc, libc, xfree86, and the kernel. This is intended for 
branch distributions, developers, and security enthusiasts.