Okay. I thought of this a while back (this morning :p) and thought "this could work", so here is the idea.
The Airship is a place where all players can venture off into maps and collect items while fighting mobs. It is a cool and unique idea for players to get higher level gear.
Now, the subway (underground) is an idea for donators (VIP+) of which the same concept occurs but has the same maps but has a couple new ones. It has higher level gear but a slightly higher mob difficulty level as well. For staying alive, you could get a ticket when you arrive back at the station which gives you like 1000 meebles (Maybe only if you get a certain amount of kills there).
With this in place, it would give a slightly better reason for donating. Also what we could do is give a bigger reward at the end to higher level donators? Only an idea but it could work.
Opinions?
Also feel free to comment ideas on top of this to make it even better. If you think it wouldn't work, then what do you think would make it work or give a reason why it wouldn't. Thanks, Jamez564
*Edit* Colour change