If you want a purebred unDOCKED Rottie, you can look for someone who breeds European stock or even import one yourself. Docking and cropping is banned in most countries other than America. European judges come to America because they LIKE the look of a docked dog, and they don't see them in their own countries, and are miffed because their country binds them legally to leaving the tails on. Breeds which served a purpose like the herding or guarding Rottie had their tails docked to eliminate an additional "handle" in situations where it would be injured, such as when herding cattle. Cows sometimes stepped on or bit tails and injured the dog, or a robber can grab a tail and hold the dog while stealing the money in the pack around it's neck. Butchers dogs were tasked with transporting the day's earnings to the bank at the end of each day.
The American Rottie Club officers PREFERS the tail DOCKED, for many reasons. They have just this year changed the standard to make the tail a serious fault if left intact. If we start leaving the tails on the dogs, we will have to gradually change the entire rear assembly of the dog since we don't know exactly HOW the tail will hang (or not in some cases they are held "gay" which is completely curled over the back exposing the butthole, and are sometimes even bare, with no hair at all!
) the dog's conformation is defined in the breed standard, and is described according to the existing lack of a tail.
As a breeder, I would never choose a 3 day old pup to leave a tail and dock the rest. I show my dogs and if the one WITH the tail turned out to be the best, i have given it a major breed ring fault!! Ths greatly reduces the chances of the dog winning.
I myself feel a rottie is a rottie with or without a tail. Rottncop HATES the tails. So the battle rages on....i hope this helps.
Oh and BTW i band tails, which is exactly the same way extra human fingers are removed. When they figure out a new way to do this, i may consider changing how i remove tails. Newborn pups experience pain completely differently than older dogs, due to their immature nervous systems. They can't even shivver if they're cold. It causes no lasting effect what so ever aside from no longer having the tail.
You could also go to a back yard breeder. I'm sure if you pay for a puppy up front they'll keep one on for you. Or you could go for a rottie mix.