Played runescape very shortly. Kinda liked the game, but i had a problem with the average user there, so dropped it after a few days.
Played Tibia for quite a long time, it is closed source, but they have a linux client (x86 but since it's all 2d graphics, a port of the client might not be that hard). Maybe the number of pandora's in the wild would probably first have to be higher to make it financial interesting for CipSoft, but then again, they have a scaled down version of the game for mobiles (it is kinda lame) so they might find it interesting to have a proper mobile platform for their full game. And i cant think of any device better equipped than the pandora.
Eniko seems to know what she's doing, and as soon as testing opens i'm going to spend a lot of time there i think, but it will be quite some time before it is an actual "Hey fck, the sun is coming up again, i've been gaming for 10 hours straight" kinda mmorpg. Very very promising, but also very early. Keep it up Eniko, and i hope you prove me very wrong!!!