I have and know many others who have as well. Its relatively easy to go undefeated for long periods of time in the earlier stages of the game and at the highest of levels with a well built account. Players that level via battling often times exceed that mark as well considering they can hit the same player 5k times per day. As far as what or who has the most consecutive victories ...hard to say as achievements dont go that high and only current streaks are recorded.
If it is done without a leveling partner, it would be impressive,if not, anyone can do that if they want to sit around and take turns clicking lol
@Linda Yes it was done without a leveling partner @polishpimp is that attacking the same person 5k per day, a leveling partner Linda mentioned?
It certainly can be and in most cases probably is, but it certainly doesnt need to be. Ive never been a big battle leveler myself but I disagree with Linda that battle leveling somehow diminishes this feat. Those players are still there clicking away and are just as vulnerable to being attacked if not more so by someone else who may beat them. Battle leveling takes a great deal of time and one must be out of the hospital and active to do so.....hence the vulnerability.