How can I improve my gluten-free pizza dough? I've been making pizza dough for years, and recently found that I have a gluten allergy, and can no longer eat wheat flour! Very sad news, indeed.

So... I bought Bob's Red Mill Gluten Free Pizza dough mix, which has a bit of xantham gum in it, and serval kinds of flour (rice flour, tapioca, flour, corn flour, etc). The dough itself was difficult to work with, a bit crumbly, and not as stretchy as I would like. I know that the "stretch" I'm talking about truly come from gluten, but is there anything I can add, to help with the consistency? The flavor was perfect, and the calzones were wonderful, they were just really hard to form...

Thanks for your help!
It seems like a lot of recipes recomend gelatin, which could add to the stretchyness. I frequent serious eats and a while ago they posted this recipe and they claim that it is great and stretchy.

http://www.seriouseats.com/recipes/2011/04/gluten-free-tuesday-easy-pizza-crust-recipe.html