This is my last Doberman, Mavis, wearing her Granite Gear Dog Pack:
And here is Half-Dobie (and half something else) Katie wearing a different type:
Here's a link for Mavis' pack:
http://www.rei.com/online/store/Pro...productId=47641338&parent_category_rn=4500452
She was a good-sized girl, and she wore a large sized pack.
I got my packs at REI. Here's what they have now:
http://www.rei.com/online/store/Sea...&cm_re=TOC_Dog_Packs&vcat=REI_SSHP_PICNIC_TOC
If you have an REI near you, they will let you bring your Dobie in the store with you to try on packs.
I really like the Granite Gear model. It's easy to put on and adjust.
They say dogs can comfortably carry about a quarter to a third of their weight. Even if you filled your pack with water you would be hard pressed to exceed the weight recomendations.
They will get used to wearing a pack real quick if they know they're carrying treats. I used to have to hide the dog packs fron Mavis. If she could get to the pack at home, she would carry it around in her mouth, set it up on the sofa, and look at me like she expected to go for a hike.
You may also want to check out collapsible dog dishes:
http://www.rei.com/online/store/Sea...og_Doggie_Dinnerware&vcat=REI_SSHP_PICNIC_TOC
My current Dobie, Mensa is still too young (11 months) to be carrying a pack, I'm going to wait until she's at least a year-and-a-half.
I hope this helps!
One more thing; You don't want to have your Dobie carry anything that can break (like a camera or a bottle of wine) or anything that might be ruined if it gets wet.