My preferred carry method is via sling strap over my left shoulder. I use a carryspeed with my SLR and I love it. I don't like to take a camera bag with me and will pick one lens and one body (and perhaps flash attached) to carry around all day. This setup was fine with the SLR as the battery last all day. But the G5 battery life won't get me through a day. So what I'm looking for is a camera sling strapped sized for the G5 that I can use to hold a battery. I know blackrapid has the Cargo strap but it is way too big and overdesigned for that I want. I don't need the pocket large enough to fit an iPhone, I just want it large enough to fit a battery. I also don't need the opening flap thing to hold a billion memory cards, or business cards, etc. If there isn't a strap with a pocket built in maybe there is some type of accessory battery holder that I can strap or sew into another strap? Has anyone seen a solution like this? I hate carrying things in my pocket and don't want to have to lug around a battery in my pocket with my phone, keys, and change.