It's a possibility it'll be open to staff before players, due for bata issues, and setting up rights and what not, but what people DO NOT understand is there is A LOT of work to be done, it's not like runescape, you just log in and everything works, it's a java coded source, runescape has their own ways, professional and their actual business for these things, so my point is there is a lot of things wrong with private servers, that the owners have to decide what and how they want certain things..
So to answer your question it is not open YET, and possibly will be open sooner for game mods..
:P