I have been looking around for a small bag that attaches to a backpack strap or a strap like the absolute that can carry something like a cell phone or an mp3 player.
It would be convenient to have a bag like this on larger bags that are worn on the back to put things in so they would be easily accessible. Also it is difficult to manage a headphone cord or get to the controls of my music player from a bag that is either on my back or down at my hip.
I have seen some backpacks that have a small pocket built into the strap. I have also been looking at small camera bags, but it seems you either have to leave them slightly open to get a headphone cord through, they only have fold over covers that leave the contents exposed to the weather or they are just too big.
It would be nice to have a small bag that just fits my player and a maybe a few credit cards, that has a waterproof way to get a headphone cord through and attaches to the strap of my backpack or messenger bag so it is in front and easy to get to.
I got to wondering why Tom doesnt design something like this? I would think he could do it right.
Until Mr. Bihn has a bag like you describe you might find the Timbuk2 Dime bag or their Shagg bag useful. I have both and they are holding up well. I'll be one of the first in line for a TB bag when he has something similar available.
I have looked at the shagg bag but it has the same problem as the camera cases you have to leave the bag slightly open to get headphones through. I think this would be a problem in heavy snow or rain, especially in snow when the snow sticks to everything and your body heat can melt it. Timbuk2 used to make a bag called a slider that had a fold over flap for headphones that went into a separate compartment from the main compartment, but they no longer make that bag.
not a bag
I do wonder about a scottevest, they have internal routing for your phone and headphones. Interesting clothing.