Hah! Finally. Years ago "OutwardHound" made a small really neat canvas bag that velcroed closed and also velcroed onto your leash handle. You could stuff poo bags into it (I find the sleeve the Tribune comes in works perfectly) and so had a handy poo-pick up supply handy when I took the Calhooligans out for a walk. Alas, they stopped making the thing (though the company does still make the canvas, collapsable drinking bowl) and all I could find were heavy, clunky plastic holders or other really awkward things.
Then, in Dog Fancy magazine, saw an ad for a couple of really cool new products. One is the Dogbag Duffels, like OutwardHound, canvas zippered bags that clip onto the leash or collar and hold a supply of poo bags. Comes in a variety of colors and is under $7. They're located at http://www.dogbag.com/, click on Dogbag Duffles.
Then, some more clever folks have solved the issue of what to do with the poo when you've picked it up and now have the leashes in one hand and poo in the other and, oh, dang, now what? So they invented the Perfect Poo Pouch ( http://www.pawsitivelyperfectpoopouch.com/) in a variety of colors and prints. Even President Obama has one for his dog, Bo. The colorful pouch comes in large ($15, about 7 x 10," for dogs over 50 lbs, spaniels to shepherds + ) and small ($12, about 7 x 7," for dogs under 50 lbs, yorkies to terriers) and fastens to your leash.
So, now there's no excuse to be a tacky jerk and leave dog poo all over the street. Simply pick up the poo in the plastic bag from your little Dogbag Duffle, twist it closed and drop it into the Poo Pouch on the leash and you've still got your hands free to deal with the leash or leashes and anything else that comes up.
Plus, your dogs get to carry their own poo, but now they can do it in style!!