Coco beans are currently only found in chest's in dungeons. As for mushrooms they can grown in a dim/dark room. The rate is slow however. I myself have 3 stacks of both types.
Farming mushrooms is possible, farming cocoa beans is not. In order to farm Mushrooms you need to put them in the dark, usually an underground room. They can grow on any surface. I'm attempting this in my world and so far I can get red mushrooms to grow, but not brown., if anyone has any tips for growing brown mushrooms it would be greatly appreciated!
Make a large room 2 blocks tall. Every 6 blocks, pop out a block in the ceiling and put a torch in. That should be a little more light than necessary to stop mobs from spawning.
Mushrooms spawn new mushrooms 1 square away in adjacent squares and diagonals. In other words, pretend they're the 5 key on your numberpad and you should see mushrooms in every other number. It's less likely they'll grow vertically, so try to make enough to room to be entirely flat. Harvest often for the maximum yield.
Or just wait and eventually they should cover everything. It's not a very fast process. I'm pretty sure red and brown mushrooms grow at the same rate.
My red took off the past couple days... My browns are growing just not at the pace the reds are... I have a 10x10 dirt room with 2 glowstones recessed into the ceiling and they're taking off like crazy.
Note: The Nether has TONS of shrooms, if you need them quickly.
http://www.minecraftwiki.net/wiki/Brown_Mushroom#Brown_Mushrooms
Mushrooms spawn new mushrooms 1 square away in adjacent squares and diagonals. In other words, pretend they're the 5 key on your numberpad and you should see mushrooms in every other number. It's less likely they'll grow vertically, so try to make enough to room to be entirely flat. Harvest often for the maximum yield.
Or just wait and eventually they should cover everything. It's not a very fast process. I'm pretty sure red and brown mushrooms grow at the same rate.
Note: The Nether has TONS of shrooms, if you need them quickly.