Okay, first of all, that's my favorite city in the world and I lived there for six months. Second, I really do not like vegetalia! In fact, as my review for the place states, I had one of the worst meals of my life there.
Where you need to go is wherever Antonio is now. This is his bakery's myspace profile: www.myspace.com/lujuriavegana
He is an amazing vegan baker and chef. He's also one of the worlds nicest people. Last I spoke with him, he was head chef at a restaurant there. I just can't remember where. Send him a message. If you leave Barcelona without eating his deserts you have failed. I have eaten at places like Millennium, Blossom, etc. This kid makes dishes as good or better than any of those places. Plus, your life will be better for knowing him! Every time I've ever met anybody who knows Antonio, a giant smile erupts on their face as his name is mentioned.
There are MANY fantastic places to eat in Barcelona. Check out the Green Earth Guide: Traveling Naturally in Spain as well as the maps to health food stores and natural restaurants in Barcelona at: www.travelingnaturally.com/gegspain.htm