I dont realy like the idea because you can still tele to citys that are close to your friends and adding an extra tele would probably be used for speeding up your training by having your friend at the training area and teleing to him. Its an interesting idea but i dont think its necessary. Walking isnt that bad. But i dont think teleporting to different servers would be very straight forward for jagex. This is how i think it works im not necessarily right, there are 120 or so servers that are all indepentant to each other. There is a friends list server(or maybe multiple) it handles private chat messages and notifiying you when your friends log in and out. There are also the log in servers there are i think 8 of these(each player is assigned to one of these). Teleing to another world that your friend is in would require the two worlds your in, the friends server and the log in server to work together to tele you there. So it probably wouldnt be very easy for jagex to do. But im sure if they tried they could do it. It would be a difficult feat i think.