I got mine from LL Bean, it's a hiker/xc-skier/what ever, hip/waist or fanny pack with two bottle holders.
My pack is 12"w x 8" deep x 10" tall....It's the largest I've seen available locally.
Here's a pic of a smaller pack, but the same general idea.
Sling packs don't work for me, I've got too much in the way to slide the pack around my body comfortably to access it when wading.
I'll stick to the fanny pack for now, I like the fact that my upper torso is free to cast and no straps are pulling down on my neck or back. The other HUGE plus is when the weather gets hot, I stay nice and cool with the fanny pack.
The only drawback I've had is if you frequently wade deep, it's going to get wet. I adjust the pack up higher when this is the case.
Nothing wrong with Vest TGW, just that you eventually want to pack every dam fishing thing you own into it....It's like owning a very large purse