Quinoa is an excellent option and should work fine.
Let me know how it works
So I tried it with the southwest and corn burgers, yesterday. My wife didn't think it worked as well as the rice would have to absorb liquid and make for a firmer burger, but I thought the texture of the quinoa was quite good. I got the idea because I make a spanish rice using quinoa in place of rice each week, and if I mix it into beans to form a burrito filling, the quinoa reminds of the texture of ground beef in a sloppy joe. So I thought it would help make the burgers more like traditional hamburgers. I explained that, and then I got yelled at for trying to make the foods I eat too much like foods from my earlier days.
I guess the bottom line is that I think the quinoa does produce a texture more like ground beef than I'd imagine rice would have. But I guess I won't know for sure until I try them with the rice. As far as flavor goes, I think most of it comes from the other ingrediants, so I don't think it should make much difference. I'm going to mess around with them to see if I can get them into good meatballs for pasta as suggested on the video. But I suppose that may take a while. I can see why you tend to make many batches at once.
It tasted great, though, Jeff. Thanks for the recipes. Do you think you'll be making these at Farms 2 Forks?