Imagine a long-sleeve T-shirt made of a modern wicking fabric, not as warm as polypro but not a thin fabric either. Something to create a light layer that is almost polypro, the thickness of a T-shirt, really. The characteristics I'm interested in are ultralight and ability to compact as small as possible, and a modern wicking fabric. It seems easy to find every characteristic I'm describing except compactability. Does anyone have a favorite shirt that fits this description? Thanks.