You cerainly can do standard line level audio on a 2.5mm TRS plug so mabe I'm just not up to speed on what laptops are including for jacks. One thing to keep in mind, ...

I've got a pair of Harman/Kardon headphones I really like the sound of, but I want to use them with devices using CTIA standard connectors. Unfortunately, the inline mic won't work in this case ...