I've been trying to do more plant-based protein too. I'm not that fond of lentils though, I try but mostly I eat them out of a sense of duty. I bought some fancy French green lentils because foodie people claim they are really great. But haven't made them yet, because I just reorganized the kitchen cabinet and pulled out all the half-bags of lentils and peas and beans to try to finish up first. I did find a recipe for cookies with lentils in them from Alton Brown so maybe I will try that this weekend... only uses up 2/3 of a cup though.
People associate grains with carbs but whole grains have a good bit of protein too. I try to eat only whole grain, and in fact eat a lot of whole-kernel grains cooked, mostly as breakfast cereal or in cold salads. Or soak and put into bread or muffins. You can find them in the "health food" section (Bob's Red Mill is the brand I see the most in the US supermarkets) as "berries." Although they are cheaper in a store that carries them in the bulk section, and if you keep them dry they last forever. Over here they mostly come from German companies. They do take a while to cook -- you basically cook them like rice -- but after they are done you can store them several days in the fridge, or freeze them for speedy microwaving.
Ex. Wheat (spelt) berries 1/4 cup dry: 4g fiber, 6g protein for 32g carb and 150cal
Rye berries 1/4 cup dry: 6 g fiber, 6g protein for 33g carb and 150cal
Pearl barley 14 cup dry: 8 g fiber, 5g protein for 39g carb and 180cal
(All these taken from the Bob's Red Mill page http://www.bobsredmill.com/grains-be...eds/index2.htm