So far the only server that's been confirmed is iZone.
iKingdoms was in production, but there's been no word of progress lately and the server is actually gone from the server list. Ol' West is on the server list, but nothing has been heard about it. iKingdoms and Ol' West are under the same management who has yet more responsibilities on Graal. And of course he keeps saying he has some real life conflictions preventing him from working on Graal at all.
Delteria is under heavy production. I'm a beta tester or something there, and it's hard to say whether or not the server looks promising. It certainly looks fantastic, but I have to keep in mind that almost all of the content was created long ago. While it looks great I don't know for sure how much of that work is recent. I hope that the server succeeds and I have no reason to believe that it won't, but it's by no means 100% upcoming or confirmed by Stefan.
From what I understand Rudora is not under production but just a testing server for Skyld to test stuff on. I'm pretty sure that that's out of the picture. (Maybe it will crop back up later on.)
iZodiac was worked on by fp4. (I don't know how long.) Since then, however, he's stated that he'll no longer be personally continuing with the project. Stefan has stated that the server will be continued, but it seems he's busy with other projects. Plus...without fp4....
Esteria was developing for iPhone, but they've since decided to make a stand-alone game instead of a part of Graal. So you may see Esteria on the app store, and I'm sure lots of Graal players will play it, but it won't be a part of Graal.
Some other servers have expressed interest in becoming an iPhone server, but their affairs are private and I really don't know much of anything about any of them. Most are likely not promising and just a bunch of novice owners with no knowledge of development, but hey, you never know.
Hope this helps.