I have found it: the Alternative Apparel burnout deep V with pocket. I love this t-shirt. It drapes really well, has a slightly boyish cut (it is unisex), and is so soft and comfortable. It's not see-through, unlike some burnout styles, and I think I need it in every colour. I'm wearing this colour, "washed black," at the moment. It is the Jane Birkin of t-shirts.
It is also perfect for my fall fashion concept, such as it is, which happens to be a lot like Tara-Lynn's. Bring on the dead leaves!