I've been running two cycles for about 2.5 days now on and off. I've killed around 100 couriers (ruined my Ally Di'Zok faction) and no ring yet. Somewhere between 2006 and 2009 they must have completely changed the drop rate as I should have seen at least one if not two rings by now. The post below details an absurd amount of couriers killed also so I am left to believe that the drop rate is now around one ring for every 150 couriers. There are indeed two cycles from the windmill going north towards the Firiona Vie stream. Mobs can spawn as far south as the windmill up to the lake and as far north as almost to the Firiona Vie stream, just near the lake edge. The only mobs that will show up on these cycles are as follows:
A Sarnak Courier (of course)
A sabertooth tigress (uncommon)
A Goblin Brawler (common)
A Goblin Skirmisher (sommon)
An Iksar Marauder (not so common but more common than tigresses)
An Iksar Brigand (same for marauder)
Greater Scalebone (common)
Greater Skeleton (common)
A Sarnak Youth (not as common as iksars)
A Sarnak Flunkie (not as common as iksars)
A Sabertooh Cat (common)
If anyone is familiar with MQ2, you can use this to keep the cycles moving very fast. It's handy if you know what you're doing, much in the same sense as Quillmane. Also, I've noticed that there is indeed a third cycle from the windmill to the Sarnak fort than can be ran with a box or a friend helping. On top of that there are FOUR to FIVE more cycles in the large open field north east from the Sarnak Fort. I have had up to four couriers spawning on different cycles in that area. I discovered it using MQ2 and killing yard trash in that area. I noticed four A Goblin Skirmishers on my MQ2 map and proceeded to start running the cycles to see if they pop couriers and they indeed do. The PH repop time is exactly 3 seconds from the death of the previous MOB on the cycle. The courier does show traits of the items he's carrying as he can wield any weapon he carrys including the Goblin Skinner. Since my ring has yet to drop, I cannot verify that he glows when he has the ring but someone below mentioned that he does. If he has the cloak, his backplate will be slightly discoloured. If he has the belt or if he's going to drop any random piece of defiant gear, his hands will be slightly discoloured. Other than that, all I can say is that this is the nastiest camp I have ever attempted in my 10+ years of playing Everquest. I am a BETA veteran and I've never seen a mob with such a sh*tty drop rate.
EDIT: Today (4-24-09), I finally got my ring to drop. I am on the Seventh Hammer server. So, a sigh of relief as this item does drop. It requires a huge amount of time to sink into the camp and if you don't consistently stick with it he could potentially spawn with the ring and be bashed by a gobby. So, stick with it, keep the gobbies off him as you're tracking him down and you WILL get a ring. Persistence is key.
Edited, Apr 24th 2009 12:02am by iamtheghost

Bloodstone Ring
Goblin Gazughi Ring
Goblin Spirit Catcher
Iksar Left Hand '=|-'
Scaled Wolf Hide Belt
Scaled Wolf Hide Cloak
). Sorry for the rambling, and I hope this makes sense.