With the limited space in the rental rooms, at least on Mysidia, people have started moving to Gridania as a back-up logout, but still everyone ends back up in Ul'Dah for shouts.
The Recruit and Party search features are starting to get used more and more, so location is mattering less.
I started trying to build a leveling guide when I was still leveling, unfortunately, it was while they were changing classes/mobs/spawn locations, and while I was able to get the level 20 camps in Coerthas down, I ended up giving up.
Now that things have settled down again, I will try and map out camps (though I will not be able to test them, as I don't have any classes available to exp with).
As a general rule of thumb, obvious camps are as follows:
1-5: Just outside of town.
5-10: Look for small open areas on the maps near the first outposts. E.g. in Ul'dah going from the first camp to Horizon there is a camp just before the bottle neck. Just north of the first outpost near the mines there are ~5+ camps, and west before you get to the bottleneck there, there is another camp. All 5-10 spots are good for 1-2 person parties, a few can handle quite a few people.
In limsa, the 5-10 mobs are towards aleport, and near the dungeon. A lot of running and killing from what I have seen.
Gridania is more of a pain in my opinion to start. You have the typical starter mobs outside of town, then towards 9 ivies there are a few camps, then down towards Tranquil before the the way-station place, and also towards Emerald moss, but stay away from Humble Hearth, as there are random level 30 wolves in some tunnels that will destroy a low level class.
But, if there are people interested in finding camps, I will start looking again for positions and locations for camps (I spent a good portion of this weekend looking for Snurbles only to find a new type, not listed here, that doesn't even drop what I was looking for...), and continue my list (all of my camps listed on lodestone are still valid, I think one Apkalu camp was moved, but other than that, they stayed the same after the last mob update).