I just wanted to give a quick 2 thumbs up to 'Half Circle Ranch'! I just ordered some mecate reins, and I LOVE THEM. The slobber straps are very reasonably priced, and you can personalize them! Here's a link to their website if you'd like to take a look: Half Circle Ranch, For All of your Natural Horsemanship Needs
You can get different colored mecate reins too! Here's a link to a thread I recently posted that has pics of my horse wearing them: Show off your mecate reins!