I like the idea of getting protein as naturally and unprocessed as possible (as with all of my nutrients). Just curious, why do you feel the need to add protein? I charted my nutrients a few times since I found out I was pregnant (fellow vegan here) just to make sure I was getting the added 25 grams of protein once I hit the second tri (in addition to the .4 grams per pound you normally want). Turns out I do just fine!
Maybe try kale shakes though. I love kale (not a shake fan), but a lot of people like to do that.