Rough / Brindled Leather Gathering

I've tried many different places for gathering rough / brindled leather and so far the best place seems to be The Purple Lotus Swamp. This works best for players who can do ranged attacks (Rangers and mages that can attack from a distance). From Tarantia, take the boat to Khemi and then take the boat to The Purple Lotus Swamp. When you arrive, turn to your left so your back is to the door.

1. Go straight ahead 50 paces into a pack of swamp beakers. This is group 1.
2. From group 1, travel north 80 paces to reach group 2.
3. From group 2, follow the path going south-west. It will turn west and then lead you to group 3, a short distance from group 2.

Keep going back and forth between 2 groups until one group doesn't give you anything for 2 rounds. Then drop that group and start going back and forth between the other 2 groups until one of them doesn't give you anything for 2 rounds. Then drop that group and start going back and forth between the other 2 groups...You get the idea.
 
The mobs range from about level 20 - 36. When I was there at level 40 something, I was one-shotting them. Killing an entire group took me literally seconds. Then you move on to the next group and the respawn rate is very high so when you return to this group, you'll only have to wait a few seconds (I actually timed it) and they'll start to respawn. I gathered 100 rough and 18 brindled in 2 hours 15 minutes. That works out to 44 rough and 8 brindled per hour. I haven't seen better stats than that.