You can buy organic beef at http://www.alderspring.com/store/page4.html
for a price that is about double the usual. I linked to fatty parts and organs specifically if you need to include good, clean fats into your diet. I'm sure there are better prices somewhere. Always check your local co-ops and farmer's markets.
You can have a healthy mind while vegan/vegetarian as well. The problem with these diets is that they are extremely difficult to plan properly. Meat is a very concentrated nutrition source that can't be replaced by a single food, but must be replaced by a variety of foods that together reconstruct its properties, and hopefully surpass it. Most vegans in the US merely eliminate meat from their normal meals with no compensation. They don't even increase the portions of the sides. They are living eating incomplete meals.
What are the elements of meat that must be reconstructed? The minerals can be found by eating a combination of greens like chard and kale alongside your preferred greens. You must eat about 3 pounds of greens a day. Despite the myth, they are much less nutritionally dense than meat. This is why juicing becomes necessary. You cannot eat that insane amount of fiber. Most of these greens must be juiced. Research what style juicer is best for extracting nutrients from greens. Fat can be found in avocados, coconuts, true nuts, false nuts, certain beans, and oils. I know of no other vegan fat sources. The ones that contain cholesterol must be eaten daily. Now the protein. These must come from beans, nuts, and grains. I suggest the grains be fermented rather than cooked. This preserves their nutritional content and eliminates its negative effects. This is a traditional form of preparing grains. The amount of protein needed depends on the intensity of your strength training. In case of heavy training, the proper amount can never be consumed through food alone and must be supplemented by vegan protein isolates. Now for vitamins. An array of fruits of various types would cover it easily. Make sure to eat fruits high in antioxidants like berries. You can make juices with these in the blender because their fiber content is low enough that they don't require the use of juicer. You also need some level of fiber from somewhere. Mix the juice from the blender with the juiced greens if desired.
All that just to replace meat; however, this spectrum of foods to replace meat does surpass it. The problem lies with the cost and tedium. Eating becomes a chore under diets like this. The prospect of eating nothing but beans, nuts, and juice everyday for the next 20 years will surely damage the psyche. I just everyone try it for at least a few weeks and see how they react to it.