Hey thanks brother! I use either mil-spec Nylon thread, number 92 is fine. You can also use Kevlar thread. All are available at thethreadexchange.com. I have custom made a set of canine armor before, so that is an option for folks.
Check your milsurp stores, every now and then they have that heavy duty nylon thread that the flight equipment bubbas use to sew together pilot G-Suits and their cool little survival tools.