Pro7ein (or Pro-Seven) has 34 grams of protein per serving and is free of gluten & sugar. It has a nice flavor - I go for the chocolate - without feeling too heavy. It was recommend by a friend at Nutrishop. His wife is gluten intolerant, so he really understands.
I tried Tera'sWhey at the Arnold Classic earlier this month and really enjoyed it. It's smoother than most proteins, less chalky. It's USDA Organic with 20 grams of protein per serving. The flavor I tried (and have since purchased) is Fair Trade Organic Dark Chocolate. Yep, the chocolate is Fair Trade Certified. The whey protein is certified hormone free. The products are made in a green plant in Wisconsin with whey from local artisan cheese makers and family farms. The products are available in Organic Whey, Goat Whey, and rBGH Free Whey. They're also on Facebook.
Forza Pro is one that my boyfriend really enjoys. It's gluten free. He sticks to the Chocolate flavor. The Mint Chocolate was tasty, but it was overly sweet for me.
-------------------------------------I have not personally tried these yet, but here are others:
Core Power - This is ready-to-drink (RTD), gluten free, and available in five flavors made from real milk and honey. Fair Oaks Farms Brands hold themselves to a Code of Responsibility that includes Sustainability, Traceability, Transparency, and Animal Care & Comfort.
Hemp Protein Powder - This is available from Navitas Naturals. It's certified organic, kosher, gluten-free, raw, and vegan. The source is grown on small family farms in Canada.
Life's Basics Plant Protein - This powder is gluten free and suitable for vegetarians. The site didn't mention whether it's appropriate for vegans. The product is primarily made from peas, rice, hemp, and chia.
Muscle Milk - This RTD product from CytoSport is gluten and lactose free. It's available in five flavors.
Nectar - Made by Syntrax (and I'm not a big fan of the site), this powder has no carbs or fat. It's also gluten and lactose free. The 9 flavors are like fruit juice cocktails -- with names like Caribbean Cooler, Twisted Cherry, and Fuzzy Navel.
Rice Protein - This product from NutriBiotic claims to be the #1 vegan protein for those with allergies to whey and soy. They have a variety of flavors made from whole grain brown rice.
Protein Energizer - From Rainbow Light Nutritional Systems, it's 100% natural and gluten-free. It contains ginger, so I can't try it.
True Athlete - Made by The Vitamin Shoppe and is free of gluten, artificial colors, flavors, or sweeteners
I'm sure there are more out there, but I didn't find others that identified themselves as gluten free protein shakes/mixes. If you'd like additional ideas, be sure to visit a nutrition shop in your area.