Here is my idea for a plugin: Users can build a hotel (or something like it) and use a command to register each room's door to a list of rooms. People that want to rent a hotel room can type a command (or even add NPC support) and it will give them access to a room that is not yet taken for a certain amount of time. The users that create the hotel could specify the price per X amount of time (iConomy?). Would this be easy for a plugin developer to do?
A plugin I just released today does something a lot like this. Take a look at it and tell me if it'll work http://forums.bukkit.org/threads/rpg-mech-urent-1-0-create-rentable-doors-and-rent-them-1000.29552/
Since I received no replies after first creating this topic, I decided to make the plugin myself (with no Java knowledge). I finished it today and it works fine, but, however, it is in no position to be released without a rewrite since I made it for my server's specifications and, not to mention, I have known Java for literally 48 hours. I may rewrite it anyways as it is very bulky and end up releasing it. @DrAgonmoray That would work, but it seems like that is more for single doors.
I have 1.5-2 years of experience with Objective-C and PHP so it was not hard for me to adapt to the Java environment. However, had I not had any experience, it would probably take a little more time to get used to. Other than the actual syntax, I just used google (and these forums) to find everything I needed to get started since it is similar to other programming languages I know.
If you want some help optimizing the code and making it compatible, you could always post the link to the source here, and I'd be happy to take a look at it!