If you are up for a slightly risky way, you can always go to Rathe Mountains, and run around the Hill Giant hill. There are lots of lone lizard man warriors and mystics (which also drop the tails) running around there, and a lot of times people just kill them and leave the tails on the bodies you can just go pick up. Even with all the HG and Cyclops and Giant Skeletons running around out there as long as you keep your eyes open it can make for a good place to get your tails, and its pretty exciting compared to just hitting lizard man camps.
If you're going for this at a lower level, say 5 to 7, best bet is to go to the lizarman camp nearest to Oggok, at about pos 900, neg 900. Keep in mind that the probability of a lizarman dropping his tail is directly proportional to the level; they're very rare off the lower level lizardmen. If you can get a group together to fight one of the harder lizarman camps, this will speed up the process of getting tails. Or you can try auctioning for lizard tails from people fighting the highest level lizardmen in the zone, the ones just outside Cazic Thule, or from people coming out of Cazic Thule, if they bothered to take any tails out. This is definitely worth the effort, as it has 3 more ac (and 3 str) than a leather tunic or cured silk gi, it's an awesome piece of armor for a beastlord, especially at this level, and you'll be wearing it for quite a while.
Don't forget to check the merchants in the area as well- into Oggok as well as Grobb, if the Orge's won't bash your head in just b/c of your face. A little bit of the cash you are slowly saving up at your early levels just might buy you a piece or two for quests like these. In the long run, it's often worth it.
the 1s outside CT dont drop tails anymore the higher lvls that drop more often are across the river now and normally killed by the roaming ogre guards if you do fight them be sure to pull far enuff away dat the guards wont attack cus nothing is worse than almost having 1 killed and being KS ed by a npc.... there is at least 2 camps of lizzys cross the river but i think there is 3or4 and at least 2 of these camp has regular visits from the roamers