I know, it sounds crazy, but I played on one server that did this and it honestly made sense.
Now about the rank:
Would be lower than VIP
Would have two /sethomes
No tax on vshop?
How to obtain:
Have x amount of people who have joined say that they were recommended by you. (One recommendation by person, could be done on forums to also encourage people joining the forums and make it easier to keep track of)
Pay y amount of meebles.
How this benefits the server:
Encourages people to bring more people onto the server, which in turn leads to more publicity.