WHAT IS A "Z" LIST?
A "Z" list is an AKC registration process that tracks colors of dogs not recognized by either the parent breed club or the AKC in a particular breed. 
 

Theoretically, a "Z" list would be a fair option to register merles as merle and not roan. All merles registered at the time the "Z" list went into effect would have a "Z" in the registration number. No need to add a color or pattern to AKC registration papers to identify them. However, the parent breed club would have to keep the statistics (which would be given by an AKC statistician twice yearly) and publish it on their web site ONLY until the first "Z" registered dog was no longer living. At that point, the "Z" list would be self-supporting and all merles would be identifiable by the "Z" registration 

Here is a mini history of what the DPCA did to implement the z-system. 
 

The first albino doberman to be AKC registered was whelped in 1976, but not registered until 1979. 

Sept. 1995-DPCA took the proposal to the AKC delegate body. 

November 1995, AKC board of directors approved a program to work with Parent Clubs to develop a tracking system to identify dogs of disqualifying colors on registration papers. 

October 1996-our z tracking system went into effect. 

  At this point the DPCA maintain the z list, 
which involves requesting twice yearly updates from one of the AKC statisticians. 
 These updates are necessary for a limited period of time due to the fact when the z list went into operation it wasn't done on a retroactive basis.  Only those animals 
registered after Oct. 1996 carry a z in the prefix of their registration number. 
Within a few years there will be no living animals carrying the albino gene who don't carry the z in their registration prefix who could possibly be reproducing...at that time the z tracking system will be  able to stand by itself without any maintenance on the part of the DPCA. 

While the Z is is appropriate, AKC STILL lists the white doberman as a color. 
AKC-#199
http://www.akc.org/breeds/doberman_pinscher/color_markings.cfm
It is not an allowed color, but it IS still listed.
So either way, ASC will still need to allow AKC to have merle as a listed pattern in order to create a Z list.

*NOTE-Z-LIST UPDATE 2011:
Because the white Dobie was a recessive, and merle is a dominate gene..The Z list will NOT work as ASC proposes.
As of now, the ASC proposes to Z-List every merle cocker including ALL of it's non merle offspring. They feel they can track the merle this way, which they cannot as all dogs from a merle will have a z in it's registration number. A non merle cannot produce merle nor is it recessive and it cannot be carried down and reproduced.
Doing it this way will eventually cause a witch hunt when merles are registered out of a Ch parent and all offspring will be z-listed. Show fanciers will be pointing fingers and no one will even know where the merle is in the pedigree. Eventually all cockers will carry a z listing by doing this and no merle will ever be tracked ..especially if it's 10 generations back. And what for? There's no rhyme or reason to this.
Merle cockers just need to be able to be registered with the merle pattern with NO Z, and people will be able to track the merle that way. No confusion, no witch hunt and no finger pointing. As it is, no one wants to register their merle with the Z, since most of the offspring will not be merle and will not carry any lethal gene nor produce merle.
The standard will have to be changed to disallow a z listed dog from being shown, which will never happen.
The ASC proposes to "educate" merle fanciers that their dogs are unhealthy, not bred to standard, and a scourge to the Cocker fancy.
ASC will be looking at class action lawsuits not only from the cocker fanciers but from every other breed who has merle in their dogs.